Introduction

Cape Split, Cape Blomidon, and in particular the area around Amethyst Cove, are favorite spots for mineral collectors and hikers alike. They are included together in this article because the cliff face extends from Cape Blomidon to the tip of Cape Split. Amethyst Cove lies about halfway between the two Capes. I'm not sure when the name originated though it was used by Walker and Parsons in the 1920s. They also mention a Captain Kidd's Cove just west of Amethyst Cove. The whole area is about 25 km north of Wolfville, in King's County, Nova Scotia.

Being in the Bay of Fundy, the tides here are the highest in the world. Therefore, extreme care must be taken when collecting here. Access to Amethyst Cove is by boat or by climbing down a steep path with the aid of ropes.

History

The basalt cliffs, or trap as they used to be called, have been known to produce fine zeolites for nearly two centuries. The first reports were by Alger and Jackson in the late 1820's. Jackson later wrote,

"the visitor, in addition to the wildness and picturesque beauty of the scene, will find a field so richly stocked with interesting minerals that he will delight to linger on the spot and gather these objects of science."

Of course, being a more accessible place today, coupled with a lack of recent rockfalls, the amount of minerals that can be found in recent years is far less. Nonetheless, the unspoiled view from the shore and the tranquility make it a very special spot.

After Alger and Jackson's visits, the next recorded visit was a geology field trip of twenty students and staff led by Emmons and Hopkins from Williams College in Boston in 1835 (Hopkins 1835, Emmons 1836). They visited several spots around the Bay of Fundy including Cape Blomidon and Cape Split. They came over from Parrsboro with Dr. Gesner. Hopkins writes,

"Being ourselves of rather an adventurous disposition, and prone to climb, we left the main body of the party, and entered one of those narrow ravines by which the sandstone cliff is, here and there, indented. The ascent was winding and very precipitous... However, having gained it, we fell, immediately, into a bed of purple Amethysts imbedded in Agate. The crystals occur in Jeodes, and are among the richest ornaments which can adorn a cabinet. It will be a sufficient recommendation of their beauty, to mention that Dr. Gesner has furnished some specimens from here for the British Museum."

A decade later, Sir William Dawson begins visiting the area. In the 1891 edition of Acadian Geology, he writes

"the trap formation of Nova Scotia has become somewhat celebrated for the abundance and fineness of the specimens for which it affords"

While that report refers to the entire Bay of Fundy region, Amethyst Cove has produced its fair share of fine specimens. A Mr. A. J. Pineo, from Kentville, Kings Co., collected these shores and ran full page ads in The Canadian Science Monthly, selling School Collections, Boy's Collections, and a Blomidon Collection. Text for the last one is shown below.

Many collectors would travel up from the United States (right through to the present) to collect at the various Fundy localities. For instance, Henry W. Noyes, a collector from Portland, Maine made the trip in 1895. A label from that trip can be seen here (Wilson 2020). He advertised in The Mineral Collector, stating

"I have just returned from Cape Blomidon, N.S., and brought back with me some fine crystallized specimens of Analcime, Heulandite, black, white and yellow Stilbite, Chabazite and Natrolite, also some pretty agates for polishing."

The engraving shown below really captures the tranquility of the locality. The basalt (trap) forms the shear cliffs on top of the much softer sandstones. This section of beach is near Cape Blomidon; at Amethyst Cove the basalt extends down to ground level. Note the two people in the lower right of the engraving.

The highest tides in the world were recorded in the Minas Basin to the east of Cape Blomidon, at a height of 50 feet. The water that fills the Basin, 14 billion tonnes of it, is forced though the narrow opening between Cape Split and the Parrsboro shore to the north. Several times each day, this flow is equivalent to the output of all the world's rivers combined. These fast currents can be dangerous for boats. Likewise, collectors must also be wary to avoid being trapped by the tides. The respect demanded by the water has been captured in the very dramatic engraving below, in this case created by a storm. In fact, the name Blomidon is derived from Blow-me-down, its name in the early 1800s. In the 1700s, the area was known as Cape Porcupine.

Geology

The North Mountain basalts are exposed for nearly 200 km along the Bay of Fundy. Many distinct lava flows have been identified from the basalt exposures, and range from 3 meters to 200 meters thick. These flows have been estimated to have covered 10,000 km². Countless gas bubbles trapped in the cooling molten rock were later infilled with minerals, in what are called amygdules. These amygdules tend to be most common near the top of a particular flow because they were moving towards the surface before the rock solidified. Amygdules can be the source of specimens, but larger specimens tend to form in areas of subsequent tectonic activity - faults and breccia zones.

The basalt is part of the North Mountain formation and late Triassic in age. It overlays the red sandstones of the Blomidon formation, also of Triassic age. It is overlain by a small exposure of early Jurassic limestone at the bottom of the map area, although this is not shown due to the small size. That rock is called the McCoy Brook formation (also the Scots Bay formation). Both the sandstones and limestones are fossil bearing.

Emmons (1836) noticed the occurrence of multiple lava flows that constitute the North Mountain though at that time they were still unsure of how the different rocks were formed. He wrote,

"Trap rocks are rarely if ever stratified. If, however we are not deceived, there are places where these rocks assume such an appearance or are in fact stratified. The only place to which we can safely refer the observer is Cape Split. The stratification is, on what may be termed a large scale; the strata are thick and heavy, but the parallel lines separating the strata, may be seen one fourth of a mile."

The pictures below are taken from out on the water between the ropes to Amethyst Cove and Cape Split. The first shows layering of the basalt, but with a very interesting undulating lower layer. It is not very clear in this photo but the layers above are horizontal and fill in the dips of the lower layer. The second photo is of the same general area, showing a section of columnar basalt. The columnar basalt is not productive for minerals.

At a spot between Cape Blomidon and Amethyst Cove, near Big Eddy, is a layer of rock near the base of the basalt that appears to be a siltsone. It is very fine grained, such that no grains are visible without magnification, and it is a homogenous chocolate brown color. It is also quite tough. This rock, in places, contains nodules, dubbed 'potatoes' for their exterior appearance, as the rock separates from their surface. These nodules and other pockets contain colorless to bright white quartz, golden blocky calcite, and sometimes zeolites such as stilbite and laumontite. Pictures of the quartz and calcite are shown below. I have a specimen from this rock found in the 1960s, and it has been collected up to about 2020, but I'm told that the exposure is currently buried. Similar brown rock that is definitely sedimentary is known from Wasson Bluff and McKay Head, but it formed at the top of the basalt as the overlying sandstones from the McCoy Brook formation filled in crevaces in the basalt. At McKay Head these are vertical cracks and at Wasson's they are randomly oriented as the basalt broke up due to faulting. But this exposure is a horizontal layer near the base of the basalt, which I find difficult to understand.

Perhaps the most amazing feature of the Bay of Fundy, and particularly the Minas Basin at the eastern end, is that the highest tides in the world occur here. The quantity of water that rushes into the Bay and Basin is so great that it actually causes this part of the province to measurably deform as the landmass sinks under the weight.

Mineralogy

The most common minerals here are zeolites. Reported zeolites include stilbite, heulandite, analcime, natrolite, gmelinite, chabazite, laumontite, mesolite, mordenite, and thomsonite. Non-zeolite minerals that can be found include celadonite, magnetite, hematite, goethite, calcite, fluorapophyllite, native copper, malachite, quartz and agate. Marsh reported psilomelane. Ramsdellite was reported from Cape Split by Majmundar in 1968. In addition to the above minerals, I've also collected cuprite and other collectors have found tenorite. The agate in particular comes in a wide variety of colors and patterns and can be very attractive. Finally, from the Triassic sandstones of Cape Blomidon, gypsum var. satin spar can be found in orange and white masses.

The locality is listed in Dana for apophyllite, heulandite, stilbite, and gmelinite (and indirectly for some of the other zeolites). The crystals can also grow to large sizes. Heulandite crystals to 5 cm, gmelinite topping 2 cm, and analcimes to 5 cm (and even to 11 cm) can be found.

One mineral that I have not seen reported but might be present is nontronite. This is a black clay mineral that lines pockets in the same way as celadonite. Although it would be easily overlooked it might be worthwhile to examine specimens for this mineral.

Table 1: Minerals reported from Cape Blomidon, Amethyst Cove, and Cape Split.

Analcime - Na[AlSi₂O₆]·H₂O

Analcime is common at Amethyst Cove and excellent specimens have been found. Crystals tend to be sharp, lustrous and white, though colorless, orange, pink, and deep red crystals also occur. It can be associated with natrolite or heulandite, among other minerals. The size of the crystals commonly reaches a centimeter or two. Some quite large crystals have been found; Frondel (1935) describes a specimen in the American Museum of Natural History with an 11 cm crystal!

In the 1990s an exceptionally large pocket (for the area) was discovered. It was large enough for a person to climb mostly inside. By then reaching in the dark to the far wall of the pocket, great specimens were simply plucked from the wall. Excellent specimens to cabinet size were recovered. The pocket is no longer visible, it seems to have been covered by beach rock.

While most analcimes are white, they also occur in various shades of orange, red, and brown. In the specimen below, they appear to be green, but are actually water clear, with the green color coming from the celadonite below the crystals. Many of the crystals in the pocket show faces of the cube form, uncommon in analcime. The drawing below shows crystal drawings of ideal analcime crystals with the usual {211} trapezohedron and wth small cube {100} faces.

Calcite - CaCO₃

Calcite is less common at Amethyst Cove than on the north side of the Bay of Fundy. It is typically the last mineral to form in the pockets and veins. The example below shows simple, translucent, rhomb shaped crystals to a few millimeters in size. They are growing on top of orange analcime.

The crystal below was found at Cape Split and is about 2 cm in size. It was in the middle of a boulder that was otherwise rotten and otherwise barren of anything useful. This crystal however, is quite clear and attractive. It shows the {32·1} scalenohedron, this time modified by the {40·1} rhomb and the prism {10·0}. On the actual crystal stepped growth of the lower part of the scalenohedron has distorted the shape of the prism faces. The crystal at the base of the calcite is apophyllite.

At least some of the calcite fluoresces. Crystals found on top of some amethyst specimens fluoresce white and phosphoresce lime green. Visually the green color is the same as for the gmelinite (see later in this article) and chabazite and all are found in the same area. The spectrum has not been measured to determine if it is due to uranium.

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. 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.

Chabazite - (Ca,K₂,Na₂)₂[Al₂Si₄O₁₂]₂·12H₂O

Chabazite has been found as small pink modified crystals at Captain Kidd's Cove, just west of Amethyst Cove, with the crystal form shown in the figure below. I've seen a few other specimens of it from the area but it is not an important mineral here. The orange specimen shown below is from Cape Split and looks very similar to material from Wasson's Bluff.

Copper - Cu

Copper is rare at this location. The best examples have been found near Cape Split. A boulder containing mostly natrolite and analcime and some copper was found in 2005. The copper formed strings (to several centimeters) of crystals, each to about a millimeter. The crystals were exceptionally sharp. The copper was included within the analcime, in which case it was very bright, and extended out of and bridged between the analcimes, in which case it had a black coating of tenorite.

Cuprite - Cu₂O

This is the first report of cuprite from Amethyst Cove that I am aware of, though it is not a surprise. I have a beach worn rock (see malachite listing) with copper in zeolite that is covered by or perhaps altering to cuprite. The bright red coating is a rough microcrystalline surface. It is altering to malachite and other copper secondary minerals.

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

Apophyllite is rather common in this area, compared to most of the North Mountain. As is the case with natrolite, water-worn material is often found on the beach, but it can also be collected fresh. Unfortunately apophyllite is a difficult mineral to collect because the crystals often cleave before they can be collected. In addition, the chalky matrix that it is usually found in at this locality makes the situation more difficult. Most material is white or green. The green at Amethyst Cove can be fairly saturated at times - the green being due to trace amounts of vanadium (Rossman 1974). I have not seen a chemical analysis of apophyllite from here, but I'm assuming it is fluorapophyllite-(K) which is what is found elsewhere around the Bay of Fundy.

Francis Alger, in 1844 writes the following about apophyllite (he uses the term replacements to mean modifications),

In Nova Scotia it accompanies the other minerals of this class, and is presented under its most interesting forms in the amygdaloidal cliffs between Capes Split and Blomidon. The commonest form is that of the perfect right square prism, with no replacements. Very frequently all the solid angles are replaced by single planes, and rarely by three planes. Occasional examples of low tabular crystals, similar to the form represented on the opposite page, are implanted upon the surfaces of yellow stilbite. These are perfectly transparent, and of extreme brilliancy, occasionally presenting a delicate tinge of green or red.

On a collecting trip in 2000, I found some very interesting tabular apophyllite. The crystals were flattened along the c-axis with a strong {111} form and only a very weakly developed {100} form. They were red and white in color, the red likely due to iron. This is the 'low tabular' shape described by Alger above. The tabular form of apophyllite indicates a high temperature of formation and slower growth (Kostov 1975, Deer et al. 2009).

Walker and Parsons (1922) discuss apophyllite from different localities around the Bay of Fundy, but not specifically Amethyst Cove / Blomidon. However, they do discuss the sequence of mineralization at other localities, indicating that it forms later than the zeolites and earlier than calcite. They note that at Cape D'Or, "the only point of importance is that it was found overlying analcite". I mention that here because I have a specimen from Amethyst Cove that very nicely shows analcime forming later than the apophyllite. Thus, both orders are possible.

In the scientific literature Goßner and Kraus (1928) study the optical properties and zoning of apophyllite from Blomidon.

Goethite - Fe³⁺O(OH)

This mineral is occasionally found as micro-sized sprays included partly to wholly in amethyst. It is not common. It is interesting to note that the amethystine color of quartz is caused by ferric iron (Fe³⁺) (Holden 1925) and ferric iron is present not only in the goethite but also in the magnetite and hematite which have also been found along the shore. It most commonly forms as solid dots and less frequently as 'horsetails' or narrow sprays emerging from the dots. Less frequently, wide sprays and startbursts are found. The dots that form as the seeds for all of the goethite are not scattered evenly throughout the quartz but rather formed at a single point in the growth of the quartz. Evidence for this is that sometimes the dots are dense enough that a phantom can be observed.

The example shown below is unique in my experience. Here the goethite forms a thick seam between an earlier and later generation of amethyst. Another specimen from the same vein shows that the top, rounded surface of the goethite is black and lustrous, indicating it finished forming properly before the second generation of amethyst formed. The goethite has a nice wood grain structure.

Gmelinite-Ca - Ca₂[Al₄Si₈O₂₄]·11H₂O

In 1827, Jackson and Alger collected some material which they took for a new mineral. Samples sent to London and New York were identified as apatite and nepheline (Torrey 1829)! Jackson later performed a chemical analysis and described what he believed to be a new mineral that he named ledererite after Baron Lewis Von Lederer, Austrian ambassador to the United States, for his contributions encouraging the study of natural history (Jackson and Hayes 1834). Soon after, however, it was suggested by several mineralogists that the material might simply be gmelinite and Alger later agreed that the original material must have been gmelinite (it had all been used up in the early investigations so none was left for additional study) (Alger 1846). In 1862, new crystal measurements sustained that idea. At the request of Alger, O. C. Marsh made careful searches of the area during several visits to Nova Scotia. Finally, in 1861 some new material was found and declared by Alger to be identical to the original material. In 1867, Marsh performed new chemical analyses which proved the suspicions that ledererite was actually gmelinite (Marsh 1867). Perhaps some of the confusion lay in the habit of the crystals. Marsh states that they often tend towards a rhombohedral form - "a peculiarity rarely observed hitherto in Gmelinite." This was in comparison to crystals from Ireland and Iceland.

Gmelinite is common but not abundant in the Amethyst Cove area. It is also found further east, towards Blomidon. It occurs as beige or pinkish crystals to over 2 cm in size; quite large for the species. The crystals may be lustrous, but frequently have a matte finish. The gmelinite tends to form directly on quartz, rather than on other zeolites. There are only two chemical analyses of the original 'ledererite'. One is in the original description, but it contains phosphate, which is surely an error. The second was done by Marsh in his paper showing that 'ledererite' is actually gmelinite. However, it is interesting that these analyses show that this gmelinite is calcium-rich, in comparison to gmelinite from Two Islands and Five Islands that is sodium-rich. Based on the current zeolite definitions, these are two separate species. It is possible that gmelinite-Na is also present at Amethyst Cove, from a different environment, but there are not yet any supporting analyses that I am aware of. Marsh's analysis, which I take to be most trustworthy, gives an atomic Ca/Na ratio of 1.16. The number of silicon atoms, water, and cations (Ca+Na2+K2) all come out very close to the expected values.

Table 2: Marsh's wet-chemistry analysis of 'ledererite' from Amethyst Cove. The right-hand column shows my calculations of the atoms per unit cell, scaled to 4 aluminum atoms.

The material below is found in a different spot than the 'ledererite' and is visually different too. I'm guessing (and it is just a guess) that this is gmelinite-Na, the same gmelinite found at Two and Five Islands to the northeast, but this has not been verified.

Pictured below is a specimen of gmelinite on very pale amethystine quartz that fluoresces brightly lime green. It consists of one large crystal surrounded by many smaller crystals. This particular piece has not been tested, so it could conceivably be chabazite, but the habit and surface features suggest gmelinite. I had previously thought it might be coated by hyalite opal, but under magnification, there does not seem to be another mineral present. Note the top-right corner of the crystal is abraded and that area does not fluoresce, suggesting that only the outermost surface of the crystals contains the fluorescent activator. In the UV photo, the purple color of the quartz is an artifact of long-wave UV and very deep violet from the lamp being picked up by the camera.

Typically, fluorescent spectra tend to be very broad with only one or two peaks. This specimen gives a spectrum with four peaks. Comparing to the spectrum obtained from meta-autunite (a uranium mineral) from near Timberlea, we can see that the peaks match very well, except they are shifted to shorter wavelengths. This indicates that the activator is uranium (or more accurately the uranyl ion, UO₂²⁺), with the energy levels modified by the surrounding zeolite. The peaks are also skewed such that wavelengths longer than each peak drop in intensity less than those shorted than the peak. I'm not sure what that might indicate, if anything, about the mineral.

Just to provide further evidence that the spectrum is caused by the uranyl ion, the plot below shows the fluorescence spectra of three other minerals with uranyl as the activator, producing green fluorescence (Larsen and Raade 1991). Apologies for the poor quality of the curves, I stretched them so that the range is closer to the plot above. The species represented are gaidonnayite, opal, and thorite. In the text they write,

A complex spectrum like the one obtained for gaidonnayite is typical of urnanyl-activated minerals....the slight wavelength shifts observed in the three spectra may be the result of crystal field effects for the different hosts.

I can only speculate on the source of the uranyl, but the North Mountain Formation overlies rocks from the Upper Paleozoic Maritimes Basin and the South Mountain Batholith (Ryan and O'Beirne-Ryan 2009). Roll-front uranium deposits are known in the Basin rocks near Windsor, and I don't think it is unreasonable to think that similar hydrothermal activity transported the uranyl ions into the North Mountain formation. The overlying McCoy Brook formation at Ross Creek, not far from Amethyst Cove, is thought to have been a hot-spring and very dark smoky quartz specimens have been found there that require radiation to darken. Those occurences could be related, with hot uranyl-bearing fluids rising up through the basalt and McCoy Brook Formation.

Hematite - Fe₂O₃

Hematite seems to be rare from the area; I have only encountered it twice in twenty years, but that was without any specific attempt to look for it. The first encounter was in 1998, from a magnetite vein. Black, hexagonal, thick tabular crystals to 0.75 mm were found. Based on the habit, and the association with and similar chemistry to magnetite, I believe this is hematite.

In 2013, I found the crystals below closer to Amethyst Cove proper. They are also black and thick tabular hexagonal crystals. When sufficiently isolated, they have a UFO shape. These crystals are very sharp and lustrous too. The are coated with another unknown mineral that may be a clay or similar type mineral. Just to be absolutely sure of the identification, this material was tested using EDS in 2018 that confirmed hematite.

Below is a drawing of an ideal crystal of hematite representing the crystals above. I have not measured the actual crystals so the forms presented ({104} and {10-4}) are purely guesses at this point.

Heulandite-Ca - (Ca,Na₂)Al₂Si₇O₁₈·6H₂O

The most interesting heulandite from Amethyst Cove forms large, brownish, extremely lustrous crystals. These are amongst the best heulandites found in the Bay of Fundy. Well formed crystals to 5 cm in length have been found. Other heulandite is colorless to white. Associated minerals include analcime, laumontite, and quartz sinter. A specimen of colorless crystals from 'Cape Blomidon' was analyzed chemically and optically (Coombs et al. 1959, Appendix 3). The same data was later included in a large study of worldwide heulandite and clinoptilolite and was found to definitely be heulandite-Ca (Boles 1972) with a relatively low Si/Al ratio. Clinoptilolite is visually identical to heulandite and simply has a high Si/Al ratio and has been reported from other parts of the North Mountain. Boles (1972) shows that high Si/Al ratio corresponds to a lower refractive index (approx. <=1.495) which could be a handy diagnostic method.

The heulandite crystals tend to be simple in form, producing what appear to be rhombic prisms, with only small modifying faces. On a few occasions some very unusual heulandites have been found that are greatly exaggerated in the [010] direction with a strong {110} form, such that the crystals are disk shaped. The photo below shows an example, but it is difficult to capture in a photo.

Heulandite sometimes likes to form curved, twisted crystals reminiscent of dolomite. The sample shown below is example of this habit. In addition it is a compound crystal, with many little heulandite crystals forming the larger curved crystal. Difficult to capture in a photo.

Table 3: Chemistry of heulandite-Ca from Cape Blomidon, from Coombs et al (1959). The ideal data is for a pure calcium example.

Laumontite - CaAl₂Si₄O₁₂·4H₂O

Laumontite is not an important mineral in the area. Small amounts have been found, but I am not aware of any good specimens. The photo below shows a couple clusters tucked between large brown heulandites.

Magnetite - Fe³⁺₂Fe²⁺O₄

At one location, about a third the way from the ropes to Amethyst Cove, veins of magnetite criss-cross through a very soft brown rock. Fist-sized chunks of massive magnetite can be found at the base of the wall. Excellent steely-gray striated crystals can be found in the veins. The crystals are dodecahedral, sometimes with very small octahedral modifying faces. Unfortunately, good mineral specimens are difficult to collect as the crystals are poorly attached to the matrix and easily fall off when trying to expose them. Crystals to 2 cm have been found.

Malachite - Cu₂(CO₃)(OH)₂

Marsh (1863) lists malachite among the minerals found in the area. Wherever copper occurs in the basalts, malachite is found as a secondary mineral on the surface of copper where it is exposed to the weather. It is generally a thin powdery coating and not of much interest. A photo is included below for completeness. It is a specimen of beach-worn copper and green malachite staining. As copper is rare in this area, it is the only piece of malachite I have seen from here.

Mesolite - Na₂Ca₂Al₆Si₉O₃₀·8H₂O

A commonly reported mineral (for example see Sabina). This mineral is often indistinguishable from natrolite and the two can only be distinguished using optical or analytic techniques. That said, I believe most of the larger, more robust crystals are natrolite. The only material I've seen that has been confirmed as mesolite is a chalky mass and the very fine crystals shown below. The specimen shown was a tiny pocket with nearby pockets of hematite and a clay mineral or celadonite that was found very close the Amethyst Cove itself.

Mordenite - (Ca,Na₂,K₂)Al₂Si₁₀O₂₄·7H₂O

Henry How (1879) reports in detail on a large pocket collected by a Joseph Steele from Scot's Bay in the 1870s. The pocket was filled with clay and contained stilbite, heulandite, and balls of altered mordenite. How called the material steelite - a variety of mordenite - to honor the collector. I am not aware of any other reports of mordenite from the area. A large specimen that is proably from this find is on display in the British Musem.

Natrolite - Na₂Al₂Si₃O₁₀·2H₂O

A new visitor to the beach will probably notice many large beach-worn masses of natrolite. In fact these are mentioned in Sinkankas's Gemstones of North America (1964) as being suitable for cutting, cabochons and beads. With some hard work and a bit of luck, however, a serious collector can be rewarded with a fresh specimen of this beautiful zeolite. Some good specimens have been found near Cape Split. The crystals are sturdier than those found at Wasson's Bluff, but are still fragile. Other more delicate crystals have been found along other parts of the shore. Natrolite is commonly associated with analcime; another sodium zeolite.

Hey (1932) published data on a natrolite specimen from Blomidon in the British Museum. Data include a wet-chemical analysis, goniometric measurements, and optical measurements. The chemical data is reproduced below. Though some substitution of sodium can occur in natrolite, the end member formula is used for the ideal.

Table 4: Chemistry of natrolite from Cape Blomidon, from Hey.

Quartz - SiO₂

Of course one would expect to find the amethyst variety of quartz at Amethyst Cove. There are stories of great old finds from the mid 1900's, but I have seen no evidence of great specimens in any of the local institutional collections. That said, at the cove there is a rock slide that more or less continuously produces small amounts of amethystine quartz. The color is a light purple with the crystals being found in the centers of pockets of quartz with a bubbly outer texture. The bubbly texture might be because the quartz had an outer layer of botryoidal chalcedony at one time that later broke away. Inside some of the amethyst pockets are zeolites such as heulandite. When massive, they may be etched away with acid and scrubbing. Another associated mineral which has been found as inclusions in the amethyst is goethite which forms delicate micro-sized sprays.

A single small shattered pocket found near the magnetite zone produced some very unusual quartz. Each quartz 'crystal' is actually an aggregate of many smaller quartz crystals all oriented in the same way. The smaller crystals are each slightly offset from each other but overall still produce the shape of a larger quartz crystal. They are very bright and lustrous.

Another type of quartz worth mentioning is found in a very fine grained light chocolate brown colored rock. I've been told this rock is found near the base of the basalt, near the boundary with the underlying sandstone. This rock sometimes contains small pockets of colorless to milky white quartz, without any other mineral species present. The crystal are of the Cumberland habit, that is without prism faces. Crystal without prism faces, or with only small prism faces, are the norm in amethyst but unusual in colorless quartz.

We find a lot of material around the Bay of Fundy that is locally referred to as silicious sinter, but is actually a milky quartz, heavily included with microscopic anhydrite, and other phases. The specimen shown below is a very interesting pseudomorph that is now quartz, with somewhat banded purple and white coloring. It displays a trapezohedral form, which, along with its environment with zeolites, would suggest the crystal was at one time analcime. However the interfacial angles are not of the typical {211} trapezohedron of analcime. Instead they agree with the {322} trapezohedron, measured using edge-on photographs. Although that form is known in analcime, I'm not aware of any instances where it is the primary or sole form. Other cubic minerals, leucite and wairakite similarly are not known to occur in that form. So it remains a mystery what the original mineral was. Although it doesn't show well in the photo, the specimen actually has reasonable luster. Two views are shown, with different lighting, to accentuate the faces.

Another very interesting quartz pseudomorph was brought to my attention by collector Sean Murray. Other collectors also report having found them, but I have not seen any other specimens or photos. The specimens were found on a cove on the south side of Cape Split. There is agate in the area, but no zeolites or zeolite-associates.

The specimens consist of random arrangements of steep bipyramidal crystals varying in size from a couple millimeters to about two centimeters. The crystal faces are a little rough, but the overall shapes are well formed, with pretty sharp edges. The crystals are tetragonal, with small pinacoidal terminations, and without prism faces. Sometimes small crystals are on top of larger crystals and some of the crystals appear to be parallel growths. The only species that comes to mind, given the morphology and environment, is apophyllite. However, I have attempted to measure the interficial angles and the results do not agree with apophyllite. For apophyllite the interficial angle between the upper and low halves of the bipyramid should be 43.7 deg, while I measure roughly 54.5 deg.

Quartz var. Chalcedony / Agate - SiO₂

Some very fine agate and chalcedony, in a wide variety of colors and styles have been found all along this shoreline. Varieties include fortification, flame and lace agates. Red and yellow flame agates are highly sought after. Colors of other agates include orange, brown, and gray. The example below is an early piece from my collection, with a nice translucent gray alternating with opaque white.

Ramsdellite - Mn⁴⁺O₂

Majmundar reports this manganese mineral. It seems to be a very unusual mineral from Cape Split, but other than analytic results, nothing is said about it in the short paper. There is no description of the specimen, associated minerals, where it was found, etc.

Stilbite-Ca - NaCa₄Al₈Si₂₈O₇₂·30H₂O

As is true for the rest of the Bay of Fundy, stilbite is a commonly encountered mineral. However it is not nearly as common as at other localities. This is especially true for good specimens. However, there is a very attractive brown stilbite that is very characteristic of this area. Many local collectors refer to this as root-beer stilbite.

Some very well formed stilbite crystals have been found near Cape Split. They exhibit well-developed faces on all sides and the termination. The drawing below shows the ideal form, based on a pseudo-orthorhombic twinned crystal.

An analysis of Blomidon stilbite by X-ray fluorescence is given by Aumento (1965). The data are shown below and it is clear that this is calcium dominant stilbite.

Table 5: Chemistry of stilbite-Ca from Cape Blomidon, from Aumento.

Tenorite - CuO

Tenorite was found in 2005 as a black coating on native copper crystals from Cape Split. It was thought to be tenorite for a number of years and the identification was confirmed in 2015 by Raman spectroscopy. It does not form crystals. This was the first report of the mineral in Nova Scotia.

Thomsonite-Ca - NaCa₂Al₅Si₅O₂₀·6H₂O

In my experience, thomsonite is rare along this stretch of shoreline. However, I collected in a few boulders on the Blomidon end where the mineral was very common. Delicate sprays and mounds up to 4-5 cm were found. They were associated with heulandite and small amounts of stilbite, apophyllite, calcite and a delicate fibrous mineral. This last mineral may have been mesolite or natrolite but was not tested.

Unknown 1

Unknown white radial mineral overgrown by natrolite. The broken radial balls are bright white, compared to the grayish white color of the natrolite. In the photo, the unknown appears yellowish but that is an artifact. The unknown also has a silky luster. Mesolite is a possibility, though it doesn't look quite like other mesolite from Nova Scotia.

Conclusion

Cape Split and Amethyst Cove have excited geologists and collectors for 200 years and they still make an exciting daytrip. Large crystals of several zeolites have been found in the cliffs. Good quartz, agate, and magnetite specimens have also been found. Tiny/micro crystals have received less attention but are no less interesting. When collecting, extreme care must be taken due to the dangerous tides, the high cliffs, and the remoteness of the location.

References

Alger, F. (1846) Ledererite. in Notices of new localities of rare minerals, and reasons for uniting several supposed distinct species. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 28(190), 557–565. doi:10.1080/14786444608645471

Aumento, F. (1966) Thermal transformations of stilbite. Canadian Journal of Earth Sciences, 3(3), 351-366.

Bishop, R. (2004) The Bay of Fundy's Minas Basin; Highest Tides in the World [online]. Nova Scotia Marketing Agency. [Similar article by Bishop Online 2013].

Boles, J.R. (1972) Composition, optical properties, cell dimensions, and thermal stability of some heulandite group zeolites. American Mineralogist: 57: 1463-1493. [Online 2020]

Coombs, D.S., Ellis, A.J., Fyfe, W.S., Taylor, A.M. (1959) The zeolite facies, with comments on the interpretation of hydrothermal synthesis. Geochimica et Cosmochimica Acta: 17: 53-107.

Dawson, Sir J.W. (1891) The Geology of Nova Scotia, New Brunswick, and Prince Edward Island or Acadian Geology. 4th Edition, William Foster Brown and Co.

Deer, W.A., Howie, R.A., Zussman, J. (2009) Rock Forming Minerals: Layered Silicates Excluding Micas and Clay Minerals, Volume 3B. Geological Society of London, 314 pages. [https://books.google.ca/books?id=5WEYTb9UAwQC&pg=PA300&lpg#v=onepage&q&f=false 2020]

Emmons, E. (1836) Notice of a Scientific Expedition. American Journal of Science and Arts, vol. 30, no. 2, pg. 330-354. [Online 2015]

Ford, W.E. (1922) Dana's Textbook of Mineralogy, Third Edition. John Wiley ad Sons, Inc., New York.

Frondel, C. (1935) The Size of Crystals. The American Mineralogist, vol. 20, pg. 469-473. [Online 2020]

Fergusson, C.B. (1967) Place Names and Places of Nova Scotia. Halifax. [http://www.rootsweb.com/~nskings/placenames.html, 2020].

Goßner, B., Kraus, O. (1928). Über die chemische Zusammensetzung von Apophyllit. Zeitschrift Für Kristallographie - Crystalline Materials, 68(1-6).

Hampson, A.G. (2004) Zeolites and associated minerals of the Wolf Creek pass area: Mineral and Archuleta Counties Colorado. Rocks & Minerals, 79(5), pp. 316-324.

Hey, M. H. (1932) Studies on the zeolites. Part III. Natrollte and metanatrolite. Mineralogical Magazine, 23(139), 243-289.

Holden, E.F. (1925) The Causes of Color in Smoky Quartz and Amethyst. American Mineralogist, vol. 9, pp. 203-252. [Online 2020].

Hopkins, A. (1835) Scientific Expedition of Students of Williams College, from Boston along the Eastern Coast to St. Johns [sic] N.B. and Halifax and Windor, N.S.. The Monthly Traveller, vol. 6, pg. 445-455. [Online 2020]

How, H. (1879) Contributions to the Mineralogy of Nova Scotia, A Remarkable Deposit of Large Specimens of Altered Mordenite. The Mineralogical Magazine and Journal of the Mineralogical Society, vol. 2, art. 14, pp. 134-141. [Online 2020]

Jackson, C.T. and Hayes, A.A. (1834) A Description of a New Mineral Species from Nova Scotia. American Journal of Science, Series 1, Vol. 25, pp. 78-84.

(to get) Kostov, I. (1975) Apophyllite morphology as an example of habit modification of planar crystals. Neues Jahrbuch für Mineralogie Abhandlungen: 123(2): 128-137.

Larsen, A.O., Raade, G. (1991) Gaidonnayite from nepheline syenite pegmatite on Siktesøya in the southern part of the Oslo Region, Norway. Norsk Geologisk Tidsskrift, 71, 303-306.

Majmundar, H.H. (1969) Ramsdellite and Groutite from Nova Scotia. Canadian Mineralogist, vol. 9, pp. 718-720. [Online 2020]

Marsh, O.C. (1863) Catalogue of Mineral Localities in New Brunswick, Nova Scotia, and Newfoundland. American Journal of Science, Series 2, vol. 35, pp. 210-218. [Online 2020]

Marsh, O.C. (1867) Contributions to the Mineralogy of Nova Scotia, No. 1 - Ledererite Identical with Gmelinite. The American Journal of Science and Arts, vol. 44. [Online 2020]

Phillips, W., Allan, R., and Alger, Francis (1844) An elementary treatise on mineralogy: comprising an introduction to the science. Phillips's Mineralogy, Fifth Edition. [Online 2020].

Phillips, F.C. (1971) An Introduction to Crystallography. 4th Edition, Oliver & Boyd, Edinburgh.

Pineo, A.J. (1885) Natural History Exchange (advertisement). The Canadian Science Monthly, vol. 3, no. 8. [Online 2021].

Rossman, G.R. (1974) Optical spectroscopy of green vanadium apophyllite from Poona, India. American Mineralogist: 59: 621-622.

Ryan, R.J., O'Beirne-Ryan, A.M. (2009) Uranium occurrences in the Horton Group of the Windsor area, Nova Scotia and the environmental implications for the Maritimes Basin. Atlantic Geology, 45, 171-190.

Sabina, A.P. (1964) Rocks and Minerals for the Collector: Bay of Fundy Area. Geological Survey of Canada, Paper 64-10.

Sinkankas, J. (1959) Gemstones of North America. D. Van Nostrand Company, Inc.

Torrey, John (1829) [Nepheline, in Proceedings of the Lyceum of Natural History of New York]. American Journal of Science, 16, 207-207.

Walker, T.L., and Parsons, A.L. (1922) The Zeolites of Nova Scotia. Contributions to Canadian Mineralogy, University of Toronto Press, pp. 13-73.

Wilson, W.E. (2020) Henry Wallace Noyes (1853-1937). Mineralogical Record Biographical Archive, https://mineralogicalrecord.com/labels.asp?colid=711.

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