Minerals of Scotland

The Scottish Highlands

Minerals of the Grampians,
Cairngorms & Moray Firth

"Cairngorm Stone" - The Type Locality

Minerals of the Scottish Highlands

General Introduction & Geology & Minerals

including photographs of

beryl - manganite - grossularite - barite - lepidolite - prehnite (& xonotlite)
quartz (red quartz - smoky quartz - cairngorm stone/ morion)


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The Cairngorms

This part of the Highlands can be rather inaccessible (more of a no-go area in winter -
a time when it shows much of its beauty). It contains several important peaks, including Scotland's second highest, Ben Macdhui (2nd to Ben Nevis).

As a centre of glaciation during the last ice age, the effects of glaciation are quite apparent in the glacial troughs (glens) separating the interspersed plateaux.

Tors on some summits can attain heights of around 25 metres. The rocks themselves are the remnants of a granitic intrusion which appears to have been a laccolith.

The Cairngorm Mountains now form Britain's largest National Park area.

SMOKY QUARTZ
(Cairngorm stone - Morion).

Small black crystals from the type locality area.

CAIRNGORMS - Loch Avon.
A winter scene. (photo courtesy of R. Starkey).

CAIRNGORM MOUNTAINS (height in feet).

Cairngorms & Their Minerals

There are minerals throughout the Scottish Highlands yet to be found by collectors. But perhaps also, Mother Nature has eroded some of the finest away - many a while ago!

Garnets, epidote, clinozoisite, zoisite and other species such as actinolite, chrome diopside, talc... have a string of recorded occurences in the region.

The minerals of the Cairngorms are often associated with granitic pegmatites. Beryl crystals, topaz, microcline and quartz fragments, the traditional minerals of the mountains, are still occasionally found. More recently, micro examples of bertrandite and genthelvite have also been recorded.

GROSSULARITE
Kingussie area, Monadhliath Mts., Inverness-shire.
Intergrown crystals to 15mms.

BERYL - Bheinn a'Bhuird, Cairngorm Mountains, Aberdeenshire.
1cm part-gemmy crystals.

Cairngorm Stone

The Type Locality

The type locality for smoky quartz - where it was first described - is in the Upper Deeside area of the Cairngorm Mountains (Aberdeenshire), in the Scottish Highlands.

As a result, this variety of quartz is also sometimes referred to as "Cairngorm Stone". Here in this region, it was mined and cut into gemstones a few centuries ago.

With the depletion of local material, combined with an influx of cheaper imports from countries like Brazil in more recent decades, this industry is now almost forgotten.

The original stones found in the area were, some believe, topaz, rather than quartz, since topaz can also be found here, though this appears to be a very rare occurence.


LEPIDOLITE - Glen Buchat, Strathdon, Aberdeenshire.
Pale lilac, hexagonal crystals covering matrix with creamy feldspar (45x45mm view).

Apart from Smoky Quartz (or morion), another mineral that is closely connected to the Cairngorm Mountains is beryl. Nevertheless, as with smoky quartz, the locations for beryl in the area are limited and good finds are rare.

Beryl also can be found, apart from the Cairngorm Mountains, in such scattered areas of the Scottish Highlands as Knoydart in the west or Ben Hope in the far north.

Lepidolite (a lithium mica) and micro elbaite (if you're very lucky!) may be found near Ballater, around Glen Buchat, in a pegmatite environment.

In tin-tungsten veins in the same area, cassiterite and hubnerite as well as scheelite crystals, occasionally associated with small fluorite crystals and quartz, are some of the other minerals to be encountered in the Cairngorms.

BARITE - Portknockie, Banffshire.
A 6mm prismatic crystal with zoned hematite inclusions.

A Geological Profile

Next to Aberdeen, is what was once the largest hole in Europe - Rubislaw Quarry. Now history, the granite from Rubislaw graces many buildings in the city of Aberdeen, which proudly boasts the title of "The Granite City". Aberdeen is currently the main centre for offshore gas and oil exploitation in the North Sea.

The swarm of granitic intrusions straddling the Highlands - from the Strontian granite on the west coast, passing the Moor of Rannoch granite, to the intrusions of the east coast, including those of Aberdeen and Peterhead - belong mostly to the so-called "newer granites".

These granitic intrusions are mainly Silurian-Devonian in age and have their equivalents, in a lesser degree, in the central belt of Scotland and the Southern Uplands.

One of these intrusions in the Highlands zone - the Strontian granite in Argyll, and its mineralising fluids, created the minerals of the famous Strontian deposit (see elsewhere).

The Scottish Highlands intrusions vary in structure, rock texture and colour (from Aberdeen grey to Peterhead pink). Granodiorite is, however, fairly common to them all. Their volcanic associates, the Devonian lavas, are found further south, as in Angus, and are famed as the host rocks for the best agates found in Scotland.

The effects of glaciation are self-evident. However, metamorphism and mineralization is less noticeable and far more varied. The region also boasts the earliest plant fossil ever found, at Rhynie, in Aberdeenshire, in sedimentary rocks of Devonian age.

The regional geology of the Scottish Highlands is nevertheless rather complex and several of its facets remain unresolved.

QUARTZ - Creig an-t-Seabhaig, Ballater, Aberdeenshire.
Red quartz cystals to 1cm. with cores of Smoky Quartz; specimen: c.60x40 mms).

An interesting recent find in the region took place in Spring 2011, when collectors uncovered quartz crystals which revealed multiple generation growths, on the eastern edges of the Cairngorms National Park, near Ballater.

The photo above depicts a very dark smoky quartz specimen (morion or "cairngorm stone") from the find, overgrown by another generation of white quartz which itself is overgrown by a thin outer zone coloured red (probably as a result of hematite inclusions).

BERYL - Bheinn a'Bhuird, Cairngorm Mountains, Aberdeenshire.
A small, bi-terminated, naturally-healed crystal on smoky quartz.

North-East Scotland & Moray Firth

Outwith the Cairngorms proper, but still in the former county of Aberdeen, a variety of minerals can be found.

At Bridge of Don, just north of the city of Aberdeen itself, well-formed manganite crystals to a few millimetres have been found. Epidote also is found nearby, at Balmedie, as small crystal aggregates.

From the Frazerburgh area, groups of brownish vesuvianite crystals have been retrieved in recent years.

At Cairnie, a few miles north of Huntly, thin veins of xonotlite occur, associated with tacharanite and other species. The area around Binn Hill is covered by a forest and access to the location is now prohibited.

To the south, in the former county of Kincardine, a recent find was made of small chocolate-brown heulandite crystals resting on quartz at Todhead Point, near Stonehaven. This general area has also produced some agates over the years.

PREHNITE - Binn Hill, Cairnie, Huntly, Aberdeen.
A pale, crystalline prehnite coating with stalactitic epimorphs
after Xonotlite/ Laumontite. (area: c. 20x20 mms).

On the southern shores of the Moray Firth, there are several occurences of metamorphic minerals, including epidote, kyanite, garnet and cordierite. Barite crystals have also been found near Portknockie as crusts of small crystals.

At Portsoy (Banffshire), commercial extraction of such minerals once took place, particularly of talc.

At Lossiemouth (Moray), thin crusts of bright green pyromorphite have been found as well as much rarer, well-formed small, grey-colourless phosgenite crystals to a few millimetres. Other reported minerals include sphalerite, galena and marcasite.

The area is not really known for ore mineral species and their secondary derivatives, though there are numerous, small occurences and/or trials for manganese, lead and copper mineralization.

MANGANITE - Bridge of Don, Aberdeenshire.
A group of crystals to c 2mms.

References/ Further Reading:

UK Journal of Mines & Minerals
vol. 21, pp 8-27. "Twenty Years in Minerals: Scotland." (D.I. Green/ J.G . Todd) (2001).
Minerals of Scotland - Past & Present. (A. Livingstone) (2003). (National Museum of Scotland Publications).
Mineralogical Record.
Vol. 20, no.5, pp. 365-368. "New Data on the cause of smoky & amethystine color in quartz." (A.J. Cohen), (1989).

ACKNOWLEDGEMENT:

This website is very grateful to Roy Starkey for kindly giving permission for the use of the landscape photo of the Cairngorm Mountains on this page.

Minerals of Scotland.