Introduction

Geographically, Cape D'Or is one of the most prominent areas of land in Nova Scotia, sticking way out into the water of the Bay of Fundy. Along with nearby Cape Chignecto, it is one of the most beautiful areas of the province. Many people come to see the lighthouse and the raging tides that rip past it. Mineralogically, this area has an interesting history of copper mining. In addition to beautiful specimens of native copper, the cliffs have produced excellent specimens of zeolites and associated minerals. It is only the second known locality in the world for the germanium mineral carraraite. It is the first Nova Scotian locality for thaumasite and connellite. This page considers the cliffs on both sides of Cape D'Or, as well as Horseshoe Cove out to Cape Spencer.

It is important to note that the shoreline in this area is very rugged and the tides can be very dangerous. An unsuspecting visitor can be quickly cut off from access to high ground.

History

The copper at Cape D'Or was known and used by the Mi'kmaq before the arrival of Europeans. The French explorers de Monts and Champlain visited the Bay of Fundy in the summer of 1604, with the Mi'kmaq Grand Chief Henri Membertou as a guide. They were shown the copper at Cape D'Or, which was recorded (Lescarbot 1609) and later translated to English by Erondelle,

"From Port Royall they sailed to the Copper mine wherof we have spoken before elsewhere. It is a high rocke betweene two Bayes of the Sea, wherein the Copper is cojoyned with the stone, very faire and very pure, such as is that which is called Rozette Copper. Many Goldsmithes have seene of it in France, which doe say that under the Copper Mine there might be a golden Mine: which is very probable. For if those excrements that nature expelleth foorth be so pure, namely small peeces that are found upon the gravell at the foote of the Rocke, when it is low water, there is no doubt that the metall which is in the bowels of the earth is much more perfect, but this is a worke that requireth time."

A map produced by Nathaniel Blackmore in 1736, based on data collected in 1711-12 gives the cape an entirely different name - Cape Minas. The actual cape cannot be seen on the map; it is not very accurate. It also includes a label stating "Copper Ore among the Marble Stones Some Ogil(?) mailable". I cannot properly read the second last word, and I would guess the last word represents 'malleable'. An interesting side note about this map is that Cape Blomidon and Cape Split are called Cape Porcapine.

The earliest significant mineralogical survey of the Bay of Fundy were performed by Jackson and Alger in the early 1800s. In 1844, Francis Alger writes

"In Nova Scotia, native copper occurs in thin seams and minute filaments in the trap rocks, generally with quartz, but sometimes with zeolites. Cape D'Or is the principal locality, where detached masses have been obtained of twenty pounds in weight."

It was not until 1870 that exploration began for the purposes of mining. In 1876 (Poole) the following account is given,

"Another attempt to find copper in workable quantity in the trap rocks of Cape d'Or was made by Mr. Prendergast. A tunnel was begun at Bennett's brook on a vein carrying quartz and zeolites impregnated with copper, adjoining a dike of trap breccia."

In 1897 the Colonial Copper Company was formed and preparations for mining began. Shafts were sunk and a 35 gauge railway was constructed to a concentration plant. By 1900 all of the shafts were in development.

Three main shafts were constructed. These were the No. 1, No. 2 or Hanway Shaft, and No. 3 or Bennett Brook Opening. The Hanway Shaft was the most important. Masses and sheets of copper were encountered, although the literature does not describe large amounts. On the contrary, it appears as though the amount of metal mined was very low. Certainly, when compared to contemporary copper mines in Michigan, it is difficult to imagine any justification for this particular mine.

Perhaps not surprisingly, by 1905 the company had fallen on hard times. Various reasons are given for the downturn. One cites dropping copper prices while another states that more conglomerate was mixed with the copper making further mining too difficult. In either event, eventually the project was abandoned. The houses were moved by barge to other towns around the Minas Basin including Port Greville, Kingsport, and Windsor.

The figure below shows the area of mining around Horseshoe Cove in 1907. The figure is a detail of a much larger original map (the title was added in from another part of the map). It shows, from left to right, the wharf, the ore concentration area at the end of the railway, a boarding house, and a couple shafts. Off to the right of the figure was the Hanway Shaft.

Today remnants of the mining activities can still be seen. Workings are visible as square openings about halfway up the cliff face. On the surface, shafts still exist, now used only by bats. At Bennett Brook bricks and concrete can still be seen, but most of the workings are overgrown. Stock certificates come up for sale from time to time. Similar looking certificates were used by unrelated companies including the Old Colony Zinc and Smelting Company, West Virginia and the Seguro Mining and Milling Company, Walsenburg, Colorado.

Geology

The prominent cliffs of the cape are Jurassic age (~200 million years) basalts of the North Moutain Formation. They are part of the Central Atlantic Magmatic Province (CAMP), that covered an enormous 11 million km2. They formed before Pangaea broke up, with similar rocks being found in the eastern United States, Morocco, and even South America.

Several separate lava flows occurred and there is evidence of some erosion occurred between flows. At least six separate flows can be counted at Cape D'Or. The basalt is generally gray in color, but some flows are distinctly more brown. The cliffs north of the lighthouse on the west side of the Cape are mostly columnar, but closer to Horseshow Cove and eastward towards Cape Spencer, non-columnar rock is more common.

Amygdules are gas bubbles that were trapped in the cooling molten rock and later lined or infilled with minerals. In some places there is a high density of tiny filled amygdules, but rocks tend not to produce good mineral specimens. A few larger pockets have been observed in otherwise dense rock, where the pockets are lined with excellent crystals. The main source of specimens at Cape D'Or are veins and breccia zones. Presumably these formed after the rocks cooled and later faulted and became infilled with minerals. Below is an example of a large brecciated outcrop that has produced nice examples of mesolite associated with analcime, stilbite, and calcite. The rock around the basalt lumps is soft and erode easily, forming waterways such as the brook in the background of this photo.

There are also a couple places where there is evidence of sedimentary rock filling the spaces between the basalt. Presumably these formed when a particular flow was at the surface and surface weathering allowed tiny sand particles to fill cracks. This is observed at Wasson's Bluff and McKay Head, but what is interesting at Cape D'Or is that is it at the bottom of the cliff, with several lava flows having formed above.

There are several minerals in the basalts with links to saline water or evaporite despoits. Nova Scotia has widely distrubuted evaporite rocks from the Windsor Group (320-360 ma), so hydrothermal fluids rising through evaporite deposits into the basalt could carry with them calcium, sodium, sulfate, chlorine, and even borate. One reported mineral is barrerite, which from other localities is speculated to form through the action of seawater percolating through the rock (Di Renzo 1997). Quartz pseudomorphs after anhydrite are common at Cape D'Or and elsewhere along the north shore of Fundy. Anhydrite is water soluble and could have dissolved from underlying rocks, been redeposited in the basalt, to be dissolved again and replaced by quartz. Thaumasite, another sulfate mineral, is known to form from an alteration of anhydrite. Very small amounts of connellite that contains chlorine and sulfate, barite that contains sulfate, and datolite that contains boron have also been found as late stage minerals.

Mineralogy

Several minerals are reported from the area. I'm familiar with, in alphabetical order, analcime, calcite, chabazite, copper, cuprite, fluorapophyllite-(K), hematite, heulandite, malachite, mesolite, natrolite, quartz, stellerite, stilbite-Ca, and thomsonite. Other reported minerals include epistilbite, scolecite, barrerite, gmelinite, laumontite, magnetite, and wairakite (Pe-Piper 2002) but published data was limited to EDS for the wairakite. Sabina (2015) reports azurite, mordenite and yarrowite, again without details. Recent collecting has identified chrysocolla, tenorite, covellite, thaumasite, carraraite, connellite, and barite. Celadonite is also present. Aegirine and anorthite have been found at Cape Spencer, identified using Raman spectroscopy. Barite was discovered in 2021.

Marsh (1863) reported vivianite but gave no supporting evidence. I doubt the identification was correct and will not include it here. How (1869) listed gold, but I will not include it for the same reason.

Table 1: Minerals reported from Cape D'Or.

Aegirine - NaFe³⁺Si₂O₆

Aegirine was discovered in rock near Cape Spencer by Don Doell and described as tan blades. Identification was by Raman spectroscopy. Aegirine in basalt is very unusual. It is associated with hematite, anorthite, augite, calcite, and a clay mineral.

Analcime - NaAl(Si₂O₆)·(H₂O)

Analcime is quite common around Cape D'Or. It has been found all around the area including the Advocate side, near the lighthouse, and out towards the Hanway Shaft. Near the lighthouse, it has been found growing around copper. On the Advocate side the crystals tend to be smaller and often associated with chabazite and stilbite. They can be snow white and very lustrous. In the area of Fort Grunt, small cream to white crystals have been found, sometimes distorted and elongated, making them distinct. Unfortunately those tend not to be lustrous. The best specimen I am aware of is a large crystal (approx 7-8cm across), significant for the province, that was found alone in a pocket near the Hanway Shaft. Generally however, Cape D'Or is not an important locality for excellent analcime.

The specimen below was found in the vicinity of Fort Grunt (as memory recalls). It is very unusual in the some of the analcimes are cavernous or hollow, with only a partial shell remaining. The interiors of the shells still shows analcime faces. And, it appears as though a large patch of the specimen is oriented because certain angles catch the light from the whole area at once.

The last analcime I want to mention is a single crystal found at Bennett Brook. It is highly distorted, making it very strangely shaped. Included below are line drawings showing what is not clear from the photograph. In the line drawing, the left-hand figure is the standard view of an ideal, equant analcime. The middle drawing is the same ideal crystal rotated a few degrees to the left, so that four of the faces are perpendicular to the screen. That is, they are not visible, but pointed to by the arrows. The drawing on the right shows the same faces around the waist of the crystal, distorted to match the actual crystal, in a view that closely matches the photograph. I've chosen not to draw the faces on the top and bottom of the crystal. They are present in the real crystal, but are very small. A very bizarre and interesting crystal!

Anorthite - CaAl₂Si₂O₈

Anorthite was discovered by Don Doell as colorless cleavages in rock near Cape Spencer. Identification was by Raman spectroscopy. It is associated with hematite, aegerine, augite, calcite, and a clay mineral.

Augite - (Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

Augite was reported by Don Doell as translucent, light brown tabular crystals in rock near Cape Spencer. Identification was by Raman spectroscopy. It is associated with hematite, aegerine, anorthite, calcite, and a clay mineral.

Barite - BaSO₄

Barite has been reported from other North Mountain Formation localities in small amounts, including along the North Mountain, Five Islands, McKay Head, and Wasson's Bluff. This is the first report of barite from Cape D'Or. It was found in 2021 in a pockety vein on the side of a boulder that had fallen from higher on the cliff. It was in the general vicinty of the Hanway shaft, not that far from where the other sulfate minerals were found. The surface of crystals is about 8x4 cm with bladed white crystals to about 3 mm. Identification is both visual (crystal shape and habit) and via EDS. The barite is associated with very fine drusy quartz and chabazite. Some of the quartz and all of the chabazite formed after the barite, which is unusual, as in all the other reported cases barite seems to be the last mineral to form.

Barrerite - (Na,K,Ca_0.5)₂Al₂Si₇O₁₈·7(H₂O)

Barrerite is a rare mineral first described in 1974 and named in 1975. A second locality in Alaska was discovered only in 1997. It has since been found in many places, but it is rare. Barrerite is visually indistinguishable from stilbite and stellerite and requires analytic techniques for proper identification which is one reason why it can go unnoticed. The underlying symmetry of barrerite distinguishes it from those other minerals.

Barrerite was reported by Pe-Piper (2002) from Cape D'Or. Published data provide only electron microprobe data. It has been postulated that it forms by "direct crystallization in the presence of sea water percolating through a volcanic horizon" (Di Renzo 1997). Perhaps it can also form from hydrothermal fluids passing through evaporite deposits into basalt from below.

Calcite - CaCO₃

From experience, calcite is more abundant along the north shore of the Bay of Fundy and the south side. Cape D'Or is no exception and calcite is found throughout the cliffs. Blocky calcites, with an oriented coating of very fine grained stilbite have been found from a large vein on the Advocate side of the cape. The specimen below is a common shape for the area, terminated with a rhombohedron and with a scalenohedral waist. This one also has a second, smaller rhombohedron. The crystal drawing shows the shape of an ideal crystal. This one, like many of them, also fluoresces bright white and phosphoresces yellow-green.

Twinned crystals of calcite have been found far along the Advocate side of the cape, associated with stilbite and chabazite. These were found in rockslide boulders; the mineralized rock is near the top of the cliffs, while the lower layers are barren. The crystals are twinned along the c-axis and most interestingly, the two component halves overlap each other, indicating a penetration twin. The crystals were a few millimeters in size and fairly complex.

Micro sized calcites have been found impaled on mesolite/natrolite needles. They are very delicate but very beautiful. The ones shown below are simple rhombs in shape, sharp, colorless, and transparent.

Herbert Whitlock (1927), in his study of calcite from the New Jersey basalts, mentions the habit of calcite,

"The dominant negative rhombohedron f. (02-21) of Type II is traceable with much greater ease throughout the literature of calcite. ... [I've] also observed this habit on crystals from ... Cape D'Or and Two Islands, Nova Scotia."

where his 'Type II' is simply crystals dominated by the forms f. {02-21} and m. {40-41}. In my experience, this habit is very common at Partridge Island, but uncommon at best from Cape D'Or and Two Islands.

Carraraite - Ca₃(SO₄)(Ge(OH)₆)(CO₃)·12H₂O

This mineral was identified in 2013 by Don Doell and the RRUFF Project (U. Arizona, see details), from material collected in 2005 and noted by Terry Collett. It is an extremely rare mineral, previously known from only a small amount of material from a single locality in Italy (Merlino 2001). In that case, it was found in a very different environment - in marble. The germanium is totally unexpected in the basalt. The identification began with Raman (gave a good signal, but not one already in the database) and was confirmed using single-crystal XRD and EDS. Carraraite is the germanium analogue of thaumasite, which was also found within a few meters of the carraraite.

Carraraite forms simple hexagonal prismatic crystals, white to bluish-white in color, and striated along their length. They are associated with mounded pale green apophyllite, stellerite, chabazite, and calcite. The crystals are often in randomly arranged clusters and the crystals reach about 2 mm in size.

Celadonite - K(Mg,Fe²⁺)(Fe³⁺,Al)(Si₄O₁₀)(OH)₂

Celadonite (not to be confused with the mineral caledonite), is a member of the muscovite mica group of minerals. It was usually the first mineral to form in the amygdules and sometimes in veins. Sometimes when a relatively smoothly shaped pocket is found, the minerals will easily separate from the basalt matrix due to the poor adhesion of the celadonite. In these cases the celadonite can be seen as a green coating on the outside of the pocket. No crystals are found. In 2021 a series of pockets were found with quite thick layers of celadonite, sometimes coating vermiform goethite. Identification was confirmed using EDS and Raman. The atomic percents of the EDS analysis were K=12.0, Mg=11.7, Fe=14.8, Si=59.1, Al=2.0, Na=0.2, F=0.1.

Chabazite - CaAl₂Si₄O₁₂·6(H₂O)

Chabazite has been found in several spots in a wide variety of colors. Small peach colored crystals are associated with mesolite, stilbite, and calcite in one breccia zone. It has also been found as good larger white crystals and smaller mirror lustrous white crystals with similarly white and lustrous heulandite. An isolated find produced some excellent and unusual brown crystals, of exceptional mirror luster.

The quality of chabazite from Cape D'Or, in terms of individual crystals, is very high; the luster is the best in the province. Despite that, good display pieces are rare. Some crystals such as the brown ones mentioned above, display shallow rhomb shaped growth hillocks on their faces which is rare for Nova Scotian chabazite.

Some of the crystals from Cape D'Or reach enormous sizes. Some of the large crystals are crumbly, but some have been found with excellent integrity. The largest I have seen is 5 cm on edge and 6 cm diagonal across the face. There are a few places in world that report larger crystals, but I have not seen photos, so it is unclear if they actually look good.

Chrysocolla - Cu_2-xAl_x(H_2-xSiO₅)(OH)₄·n(H₂O), x<1

This mineral is quite widespread and commonly found with copper. It is blue-green, but seems to range from a more green color to quite blue. It does not form crystals - it is only found in massive form. However it does form gel-like coatings on copper, fingers, and stringy root-like growths that can make attractive micro material. Identification of most pieces is visual and but it has been confirmed with EDS analysis, performed in 2018.

Connellite - Cu₁₉(SO₄)(OH)₃₂Cl₄·3H₂O

Vibrant blue in color, sometimes with a radial structure. The aggregates are small, reaching only a couple millimeters in diameter and are embedded in chrysocolla so that they do not form free growing crystals. It often appears that it grades into chrysocolla. Besides chrysocolla, it is associated with native copper, cuprite, chrysocolla, chabazite, and calcite. It was spotted by Terry Collett in material collected near Cape Spencer in 2015. EDS was performed in 2018 and showed Cu, S, and Cl. This is the first report of this species in Nova Scotia.

Connellite has been found with zeolites at Flinders, Australia (Birch and Pearson 1982). It was accompanied by another copper chloride mineral, paratacamite. That is also a shoreline locality. They could not verify the source of the chloride but speculated it was from the seawater. At Cape D'Or I doubt it was recently formed recently due to seawater. I suspect the sulfate derives from earlier anhydrite in the rocks, in the same way that thaumasite formed.

Copper - Cu

Copper is common from the locality. Mining reports describe the ore as fine grains and thin plates. Recently collected specimens include arborescent growths and crystals. The size of the crystals can reach several centimeters. Red coatings of cuprite are found on any of the specimens. Sometimes the cuprites form bright sharp micro crystals. If the copper is found sticking out from the rock, the cuprite on the exposed areas is altered to powdery malachite.

The recently collected copper comes from thin joints and fractures in the basalt (not from the mine workings). In some cases the copper follows a bend or junction in the fractures, but most of the specimens are rather flat. When found, the specimens are generally encased in a soft black material which appears to be altered basalt along with zeolites such as stilbite and analcime. The laborious task of cleaning the specimens, under a microscope with a needle, is necessary to reveal the true beauty of the mineral.

The crystals take on a variety of forms and in some cases are very sharp. Although sharp, they are typically quite distorted and elongated, making it very difficult to visually determine what types of forms are present. Still, occasionally equant crystals are found. Below is a set of crystal drawings and photographs showing a progression from a pure cube to a nearly dodecahedral crystal. Several examples of cube-only crystals have been found; they are rare worldwide.

Copper is frequently known to twin, but often the morphology is so complex that it can difficult to see clearly. In the crystal shown below the repeated twinning is made obvious by the changing direction of the striations. The effect is dramatic and attractive. Interestingly the overall crystal shape is simple and blocky. If it were not for the striations, the shape would not suggest a twin.

Covellite - CuS

Covellite was identified by Raman spectroscopy in 2013 using material collected near the lighthouse. Later the same year crystals were found west of Bennett Brook. The crystals are black, sometimes with a blue iridescence, and dull to lustrous. They occur in loose mounds with individual crystals generally below 1 mm though some larger crystals to 1 cm were also found. Well formed crystals are striated, tapered, blocky to tabular, with a hexagonal outline. The crystals are coated in green copper secondaries (chrysocolla) and associated with chabazite and stilbite. Under a microscope, a needle can be used to flake off the chrysocolla, revealing the crystals. Unfortunately, covellite is brittle and has excellent cleavage, so crystals are easily damaged. The specimen below was also verified by Raman, in 2021.

Cuprite - Cu₂O

The first report of cuprite from Cape D'Or that I can find is How (1869), where it is listed as red copper. Cuprite is frequently found as on the surface on copper specimens, making them red in color. Nearly always, the cuprite so finely crystallized that crystals are not visible, or the coating is powdery. Some specimens show excellent crystal development under high magnification, typically octahedral but cubes are also known. At their best, these crystals are sharp, gemmy, and bright cherry red - the sepcimen shown below is the finest example I have seen. Despite the limitations of the photo, the crystals are razor sharp and brilliantly lustrous.

Fluorapophyllite-(K) - KCa₄(Si₄O₁₀)₂F·8(H₂O)

Apophyllite is very common and has been found in a wide variety habits and colors. The first habit worth noting was found in the vicinity of the Hanway Lode in brown basalt. Pale blue-green crystal aggregates were found growing on a fine druse of creamy colored stilbite. The aggregates consisted of diverging crystals that gave an overall appearance of lumpy mounds. Despite the description, the color and form made these nice and interesting specimens.

Exceptionally lustrous, large blocky crystals have been found associated with minor mesolite, from the Bennett Brook - Fort Grunt area. In this case the apophyllite lined pockets in very hard basalt. The crystals are milky white with just the faintest hint of green. Another find of apophyllite produced white crystals with red streaks. The shape was tabular with modified corners. The crystals were somewhat etched giving a frosted appearance. Some nice specimens, with crystals growing on blades of stilbite were collected. One last find is worth noting. Small but excellent gemmy crystals were found with one of the thomsonite finds. These were colored a rich minty green and very attractive.

As already seen, the apophyllite can be white or pale green. More rarely deeper green material is found. Sometimes the apophyllite is heavily included with iron creating a vibrant orange-red color. The small red specimen shown below was found between Bennett Brook and Horseshoe Cove.

I have not seen a chemical analysis of apophyllite from Cape D'Or, but fluorapophyllite-(K) is by far the most common apophyllite species worldwide and is the one found elsewhere around the Bay of Fundy, so it is reasonable to assume the material from Cape D'Or is also that species.

Goethite - Fe³⁺O(OH)

Goethite was identified using EDS and Raman in 2021. The goethite forms yellow-brown root-like structures both within and outside of chabazite and stilbite. The specimens shown below were from a few very closely spaced pockets, and I have not encountered goethite elsewhere.

Hematite - Fe₂O₃

Coste (1888) reports hematite from Cape Spencer. Some very nice micro material has been collected from this area recently (2013). The rock is soft and reddish-brown in color. It has numerous gas bubbles, often filled with an unknown yellow-brown mineral. Some of the bubbles also contain calcite crystals. Other minerals identified include aegirine, augite, and anorthite.

The hematite forms nice lustrous sharp black crystals with trigonal symmetry. They are also magnetic, being attracted to a strong magnet, though it isn't clear how this could be. Perhaps some relationship to magnetite or ilmenite. The forms present are shown in the diagram below. The actual crystals show considerable variability, ranging from tabular to elongated. The faces of the {101} and {012} forms vary widely in size and the 101 faces are sometimes absent.

In recent years hematite var. specularite has been found as tiny flakes on the joint planes of a red colored basalt to the west of Bennett Brook.

Heulandite - (Ca,Na₂)Al₂Si₇O₁₈·6(H₂O)

This mineral appears to be far less abundant here than at most other Bay of Fundy localities. The crystals that do occur tend to be small and they are usually white or colorless, thouh reddish crystals have also been found. Some pearly curved crystals were found in a boulder partly overgrown with thomsonite and some attractive white crystals associated with chabazite were collected from another find. I've also seen it overgrowing bright copper. In terms of morphology, there are a couple forms that I've observed here that are rare or not found elsewhere around the Bay of Fundy, including {112} and {011} (using a coordinate system where the a-axis is the smallest cell dimension).

Laumontite - CaAl₂Si₄O₁₂·4(H₂O)

Laumontite is a rare mineral here. Even after dozens of trips to the area, I have never encountered it. An early report is the cataloging of a specimen from the Geological Survey of Canada collection (#5713). It was found on the west side of the Fog Whistle, or what I am calling the Advocate side, and was collected by C. W. Willimott in 1888 (Hoffmann 1893, pg 21).

Malachite - Cu₂(CO₃)(OH)₂

The vast majority of malachite from Cape D'Or is formed by weathering of exposed cuprite-coated copper. Such malachite forms powdery or dusty coatings and does not form visible crystals. The specimen below is a rare example showing malachite needles in a jumble of sprays. The larger pale-color spray seems to be malachite coated with a thin layer of chrysocolla.

Mesolite - Na₂Ca₂Al₆Si₉O₃₀·8(H₂O)

Generally speaking, mesolite is not a common mineral in Nova Scotia. However, at Cape D'Or mesolite is quite common. It occurs as beach pebbles and pocket linings. The crystals at Cape D'Or are exceedingly thin and hairlike, though in nearly all cases these have been matted by groundwater. However at the base of the crystals, they intergrow into a solid mass. This mesolite aggregate is very tough and procelanous. When tapped, it can make a tink-tink sound.

The specimen shown below was from a chain of pockets following a fault. Nearly all of the pockets are exposed to at least some groundwater, matting the needles and staining the mesolite, leaving an attractive graduated coloration.

Along another section of the beach, smaller isolated balls of mesolite form with calcite, stilbite, and chabazite in pockets in a brecciated rock. These can make attractive miniature sized specimens, with the chabazite sometimes offering a nice contrast in color with the mesolite.

On certain parts of the shore, mesolite nodules are found weathered out of the cliffs. The interesting pseudomorph, shown below, was discovered by breaking open one of the nodules from Horseshoe Cove. The replacement of the analcime is very sharp. On close inspection of the specimen, the delicate and feathery mesolite is seen in great detail. Also note the adjacent casts of analcime crystals, only partly filled with fibrous mesolite. That mesolite is brown because the specimen has not been cleaned.

While clearly (and sadly) damaged, one last specimen deserves note. This specimen consists of a spray of very long thin hairlike crystals. The crystals delicate but yet flexible. This specimen has not been tested and may be either mesolite or natrolite. Regardless, it is very unusual to find this type of specimen from Nova Scotia where the long fibers have not been matted together.

Below is a wet-chemical analysis of a mesolite beach-pebble from Cape D'Or, presented by Walker and Parsons (1922). I've omitted minor amounts of Fe2O3 and K2O, and added a column calculating the number of atoms in the formula. This data is also presented in Peng (1955), who used mesolite from Cape D'Or in a differential thermal analysis (DTA) study of natrolite-group minerals. It showed that natrolite, mesolite, and scolecite lose water at different rates when heated and DTA can be used to distinguish the species.

Table 2: Walker and Parsons wet-chemical anaylsis of mesolite from Cape D'Or.

Natrolite - Na₂Al₂Si₃O₁₀·2(H₂O)

Natrolite is rare, or at least inconspicuous, at Cape D'Or. The only time I've encountered it is as isolated hair like crystals (not sprays or pocket linings like the mesolite) on thomsonite. Pe-Piper and Miller (2002) present EDS analyses of three samples.

Quartz - SiO₂

Colorless quartz has been found in the Horseshoe Cove area, including a very good cluster of diverging crystals, shown below. In general, however, I would say quartz crystals of anything but micro size are uncommon. In fact, I do not know of another specimen with prismatic clear crystals from the Fundy. The crystals are either stubby (as in amethyst) or milky (as in some sinter specimens).

A list of Canadian minerals by Hoffmann (1889, pg 96) includes "fine specimens" of quartz after chabazite, also from Horseshoe Cove.

Quartz psuedomorphs after anhydrite have been found several times at various points along the shore. The specimen below is one example. Pseudomorphs after anhydrite (or casts after anhydrite) are well documented from the basalts of New Jersey and are frequently found at various places on the north side of the Bay of Fundy too, once you know what to look for. The have a rectangular cross section and sometimes they often get thinner at the ends and flare out a bit at the same time. This piece came from a rockfall that had huge surfaces covered with similar material.

Stilbite - NaCa₄Al₈Si₂₈O₇₂·30(H₂O)

Stilbite is a common mineral from the area. Colors include white, colorless, or orange. It is associated with nearly every other mineral. It may form druses, larger discrete blades, and crystal aggregates. One noteworthy vein produced large numbers of creamy colored crystal aggregates of good luster and excellent habit. Forms included sheaves, bowties, and complete wheels of the mineral.

It should be noted I and other collectors default to the identification of stilbite for material that looks like stilbite. While stilbite is the most common mineral, some material may be stellerite or barrerite. Those minerals are visually indistinguishable from stilbite.

In 2010 a very exciting find was made of stilbite epimorphs after mesolite. The original formation would have been mesolite on stilbite. Then a second generation of stilbite formed over the mesolite in fine crystals, forming very well formed hemispheres. The mesolite then partly to completely dissolved away leaving the stilbite shell. Most of the stilbite hemispheres were complete, but some incomplete, leaving a opening to view the remaining mesolite inside.

One last point of note is that sometimes stilbite is found on top of calcite, indicating that is formed later than the calcite. That ordering is also observed at Partridge Island.

Stellerite - CaAl₂Si₇O₁₈·7(H₂O)

Stellerite is visually indistinguishable from stilbite and requires analytic techniques for proper identification. While a small amount of sodium may be present, it is typically highly dominated by calcium. Crystal structure distinguishes it from stilbite-Ca. It has been reported by Pe-Piper (2002) and was also identified on a specimen analyzed for the RRUFF project (specimen R130410). Unfortunately, analytic data has not been published. The International Zeolite Association write that "distinguishing stellerite from stilbite requires a careful chemical analysis, a good X-ray powder pattern, and optical examination. Stellerite should have less than about 0.2 Na atoms per formula unit (72 oxygens), no splitting of the 204 peak (in the interval 23 to 24° 2?, CuKa) in the X-ray pattern, and optically straight extinction with no twinning."

Tenorite - CuO

Tenorite was found in 2015 as a black coating on native copper crystals from near Cape Spencer, in material collected by Terry Collett. Associated minerals include chabazite, cuprite and chrysocolla. The identification is visual only at the moment, but tenorite has been confirmed from Cape Split. It does not form crystals. This is the first report of the mineral from Cape D'Or.

Thaumasite - Ca₃(SO₄)(Si(OH)₆)(CO₃)·12H₂O

Thaumasite was identified from material collected in 2013 and several years earlier. It comes from a small section of brown basalt perhaps 10 m across and 4 m high, in the general vicinity of the Hanway shaft. This section of rock contains stilbite, stellerite, chabazite, apophyllite, and calcite. A single specimen of carraraite, the germanium analogue of thaumasite, was also identified. The thaumasite occurs as microscopic white needles in jackstraw arrangements, sprays, balls, and thin seams. Single crystals to 1 mm have also been found. The crystals are silky in appearance with striations along their length. It exhibits pale fluorescence. This is the first report of the mineral from Nova Scotia. Also of note, a single specimen was found a short distance from the outcrop described above. This specimen apparently came from higher on the cliff, indicating another zone of formation. This specimen had a very large mass of thaumasite several centimeters across in massive greenish apophyllite.

While thaumasite is a well known and widely reported mineral these days, it was quite a sensation when it was discovered in the late 1800s. That was due to its chemistry being both a carbonate and a sulfate (and, at the time, also thought to be a silicate). In fact the name thaumasite is derived from the Greek verb 'to be surprised'. It tends to form in one of three geologic settings. These are sulfide ore deposits, contact metamorphic zones, or as in the case of Cape D'Or, the reaction of geothermal waters or seawater with basalt and tuffs.

Thaumasite has been found with zeolites from several localities including Northern Ireland (Knill and Young 1960), Hungary (Mauritz 1931), and New Jersey (Wherry 1919) (see MinDat). The New Jersey find was in basalt deposits of the same age as Cape D'Or. There, the thaumasite was found in the late 1800s in large masses. In 1914, a collector was able to collect additional material that showed that it was derived from anhydrite, which is also found in those quarries. The collector had examples showing many stages of transformation from anhydrite to thaumasite. The discovery even made it into the New York Times in an article entitled 'Thaumasite Secret Solved by Amateur'. Schaller (1932) describes the transition from anhydrite to thaumasite via gypsum. That reports includes photos of well formed pseudomorphs.

Anhydrite and gypsum have not yet been found in the Bay of Fundy basalts. However, pseudomorphs of quartz after anhydrite are common all along the northern side of the Bay of Fundy. Perhaps the molten rock interacted with underlying evaporate deposits from the Carboniferous Windsor Group. Other sulfate minerals are also found in small quantities and are usually late forming.

Thomsonite-Ca - NaCa₂Al₅Si₅O₂₀·6(H₂O)

A wide variety of thomsonite can be found in the general area of Bennett Brook. Large balls of thomsonite, to many centimeters in diameter, have been collected. These represent the best thomsonite in the province - and excellent even when compared to thomsonite from other world localities. The only two species of thomsonite are thomsonite-Ca and thomsonite-Sr and the strontium variety is very rare. It is very safe to assume that all thomsonite from this locality is the calcium species. Wise and Tschernich (1978) write that thomsonite and mesolite are commonly associated. This is quite true at Cape D'Or where both minerals are common and frequently found together or in close proximity.

A particularly good boulder produced good thomsonite of two varieties in 2003. The large balls tend to be coarse textured as shown in the photo. On top of the larger balls, very delicate flexible hair-like natrolite crystals were sometimes found. Associated with some of the coarse thomsonites were smaller, more compact, somewhat grayish, translucent balls with a smoother surface. These too were identified as thomsonite. Associated with both of these were excellent green apophyllite, stilbite, and heulandite. Both of the habits of thomsonite, as well as the natrolite, were confirmed by powder XRD.

In 2013 an interesting specimen was found near Horseshoe Cove. The thomsonites form tight balls about 1 cm in diameter. The thomsonite, verified by Raman spectroscopy, is very translucent and the component crystals have large endfaces, making it unlike any other thomsonite I've seen from Nova Scotia. The thomsonite balls were found among balls of mesolite.

Wairakite - CaAl₂Si₄O₁₂·2(H₂O)

This mineral is the calcium analogue of analcime. It was first described in 1955, but it is rare. It may form a series with analcime, but this is uncertain (Coombs 1997). Wairakite is visually indistinguishable from analcime and requires complex tests for identification. It was reported from Cape D'Or by Pe-Piper (2002). Published data show electron microprobe analysis for a single specimen, sampled in four locations. The average Ca:Na2 ratio for those measurements was 2.8, clearly Ca dominant, but nearly as high as wairakite from New Zealand and Japan. This is the first report of the mineral in Nova Scotia (along with Wasson Bluff).

Unknown 1

A greenish-brown flaky mineral has been found associated with calcite, thomsonite, and chabazite on the Advocate side of Cape D'Or. It has also been found as inclusions in chabazite. It is not well formed in crystals, but does seem to be a mineral.

Unknown 2

The specimen below is from near Fort Grunt, between Bennett Brook and the Hanway Shaft. It has only produced a couple specimens. In my example, the crystals are strongly striated, tapered, blocky and have a hexagonal outline. Hematite and covellite are possibilities. The crystals are associated with stilbite and both minerals are partly coated with another unknown material. On the crystal in question, the coating is a vibrant bottle green color and gel-like but does not look like typical chrysocolla. On the stilbite, the coating appears yellow-brown.

Unknown 3

The crystal shown below is a thin black trigonal or hexagonal plate. Based on the green staining nearby and the environment, we can safely assume this is a copper mineral. Covellite and chalcocite are likely candidates, but the crystal has not been tested for confirmation.

Unknown 4

This mineral was found the the same rock that produced barite (see earlier). Some malachite is also present. The unknown species forms exceedingly tiny pale blue crystals. Although impossible to tell from the photo, the crystals are very thin rectangular prisms. They may be the copper sulfate mineral wroewolfeite (Cu₄SO₄(OH)₆·2H₂O), as color, shape, and associations/environment are all matches for that species. Several other sulfate species (of copper, calcium, and barium) have also been reported from Cape D'Or, all in the general vicinity of this species (the barite from this same rock). I hope to be able to get an EDS analysis of this specimen in the future and possibly a Raman spectrum.

Conclusions

With the incredible currents of the Bay of Fundy rushing past the cape, this section of shoreline is rugged and exciting. Remains can still be seen of the operations of the Colonial Copper Company a century ago. With hard work, nice specimens of crystallized native copper can be found. In addition, a variety of zeolites have been reported, including the best mesolite and thomsonite from the Bay of Fundy region. In recent years a number of microminerals have been found that are new to the Bay of Fundy including a specimen of extremely rare carraraite. Perhaps Cape D'Or is holding more surprises.

Acknowledgements

I would like to thank Paula Piilonen and Ralph Rowe at the Canadian Museum of Nature for the powder XRD of the thomsonite. Special thanks to Dick McAllister for the specimen of mesolite ps. analcime. To Terry Collett for the stilbite ps. mesolite specimen. Thanks to Don Doell and the RRUFF project for the identification of covellite and carraraite. A big thanks to the Nova Scotia Mineral and Gem Society for covering the cost of having the historical photos reproduced. To the Nova Scotia Museum and Dino Nardini for allowing me to photograph the copper sheet and the green apophyllite crystal, respectively. Finally, thanks to Xiang Yang and Saint Mary's University for the barite analysis.

References

Allen, F.I. (1915) The Origin of Thaumasite. American Journal Science, pg 134. [Online 2013]

Anonymous (1914) Thaumasite Secret Solved by Amateur. 1914 November 23, New York Times. [Online 2014]

Birch, W.D. and Pearson, J.E. (1982) Copper chloride minerals in basalt from Flinders, Victoria. Australian Mineralogist, 39, 211-213.

Blackmore, N. (1736) Bay of Fundy and harbour of Annapolis Royal. (David Rumsey Map Collection) [Online 2013]

"Colonial Copper Company", Prospectus, 1902.

Coombs D.S., et al. (1997) Recommended nomenclature for zeolite minerals: report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35, 1571-1606. [Online 2014]

Coste, E. (1888) Report on the mining & mineral statistics of Canada for the year 1887. Geological Survey Canada, Annual Report (New Series), vol. 3 part 2. [Online 2013]

Dana, Edward S. (1886) On the Crystallization of Copper. The American Journal of Science, Third Series, Article 48, pg 413-429, vol. 32, no. 192.

Di Renzo F. and Gabelica Z. (1997) Barrerite and other zeolites from Kuiu and Kupreanof Islands, Alaska. The Canadian Mineralogist, 35, 691-698.

Douglas, G.V. (1942) Preliminary Report, The Copper Deposit at Cap D'Or. Cumberland County, NS.

Fulton, J.W. (1907) Geographical Map Showing the Mineral Lands of the Colonial Copper Co., Cumberland County, Nova Scotia, 1907.

Hoffmann, G.C. (1889) Annotated List of the Minerals Occurring in Canada. Proceedings and Transactions of the Royal Society of Canada, Vol 7. [Online 2012]

Hoffmann, G.C. (1893) Catalogue of Section One of the Museum of the Geological Survey. Geological Survey of Canada. [Online 2021]

How, H. (1869) The Mineralogy of Nova Scotia. A Report to the Provincial Government. Charles Annand (Publisher), Halifax, Nova Scotia. [Online 2013]

Knill, D.C., Young, B.R. (1960) Thaumasite from Co. Down, Northern Ireland. Mineralogical Magaazine: 32: 416-418.

Lescarbot, M. (1609) Nova Francia, or The description of that part of New France which is one continent with Virginia. Londini: Impensis Georgii Bishop. [Online 2019]

Marsh, B.A. (1863) Catalogue of Mineral Localities in New Brunswick, Nova Scotia, and Newfoundland. American Journal of Science, Series 2, Vol. 35, pp. 210-218. [Online 2012]

Mauritz, B. (1931) Die Zeolithmineralien der Basalte des Plattenseegebietes in Ungarn. Neues Jahrbuch fur Min. etc. Beilage Band 64, Abt. A, p. 477-494.

Merlino, S. and Orlandi, P. (2001) Carraraite and zaccagnaite, two new minerals from the Carrara marble quarries: their chemical compositions, physical properties, and structural features. American Mineralogist, 86, 1293-1301.

Messervey, J.P. (1929) Copper in Nova Scotia. Pamphlet No. 7, Nova Scotia Dept. of Public Works and Mines.

Penfield, S.L. and Pratt, J.H. (1896) On the Occurrence of Thaumasite at West Paterson, New Jersey. The American Journal of Science, ser. 4, vol. 1, Art. 24, 229-233. [Online 2013]

Peng C.J. (1955) Thermal analysis study of the natrolite group. American Mineralogist, vol. 40, no. 9-10, 834-856.

Pe-Piper, G. and Miller, L. (2002) Zeolite minerals from the North Shore of the Minas Basin, Nova Scotia. Atlantic Geology, 38, pp. 11-28. [Online 2013]

Phillips, W., Allan, R., and Alger, F. (1844) An elementary treatise on mineralogy: comprising an introduction to the science. Phillips's Mineralogy, Fifth Edition.

Poole, H.S. (1877) Annual Report on Mines 1876. vol. 5. [Online 2015]

Sabina, A.P. (2015) Rocks and minerals for the collector: Bay of Fundy, New Brunswick and Nova Scotia; South Shore, Nova Scotia. Geological Survey of Canada, Popular Geoscience 97: 456 pages, doi:10.4095/293933

Schaller, W.T. (1932) The Crystal Cavities of the New Jersey Zeolite Region. U.S. Geological Survey, Bulletin 832. [Online 2013]

Wherry, E.T. (1919) Notes on mimetite, thaumasite, and wavellite. Proceedings of the U.S. Natural History Museum, 54, 373-381 (375-379).

Whitlock, H.P. (1927) A study of the crystallography of the calcites of the New Jersey diabase region. Bulletin of The American Museum of Natural History, 56, 351-377.

Wilson, M.L. and Dyl, S.J. II (1992) Michigan Copper Country. The Mineralogical Record, vol. 23, no. 2, April-March 1992.

Wise, W.S. and Tschernich, R.W. (1978) Habits, Crystal Forms and Composition of Thomsonite. Canadian Mineralogist, vol. 16 p. 487-493. [Online 2020]

Disclaimer: This page is intended for information purposes only. The locality is not necessarily open to collecting. The locality is not necessarily safe.