Strontian

Strontian - Minerals

Strontian - Mines

Fee Donald Mine
Corrantee Mine
Bellsgrove Mine
Whitesmith Mine
Clashgorm/ Middleshop Section

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Strontium - ithe element and its properties - www.webelements.com

Strontian - the village and its surrounding area - Strontian

STRONTIAN - The Location

Strontian is a small village in the county of Argyll, attractively located on Loch Sunart in the western Highlands of Scotland. It si also situated close to the mouth of the Great Glen and the island of Mull. The name, Strontian, derives from the Scots Gaelic language
meaning "point of the fairies".

The mining site is actually a couple of miles from the village of Strontian, near Beinn Resipol, a peak reaching 847 metres, and the locality is also known as Scotstown.

The mineralization is related to the neighbouring, granitic intrusion - the Strontian Granite - one of a series of intrusions, called the "newer granites", straddling Scotland's Grampian Highlands and which are mostly Devonian in age.

Mining at Strontian

Between 1722 and 1904, silver, lead and zinc were extracted from the mines. Galena was the main ore mineral on which attention centred during this period. However, in the 1980s, mining subsequently focused on the extraction of barite for use in the North Sea oilfields; the milled barite being used to increase the density of drilling fluids or "muds" for drilling oil/gas wells. Density is adjusted to control various reservoir pressures as well as maintain wellbore stability.*

Over its long and irregular history of mining activities, several areas have been exploited, including the Corrantee, Middleshop and Fee Donald Mines from earlier periods, and also the Bellsgrove and Whitesmith Mines - names which will resonate with mineral collectors from around the world.

Historical Background

Strontian has an important position in the history of science.
Here, in 1790, Adair Crawford, a Scots-Irish chemist, "discovered" the mineral species, strontianite and determined a new chemical element was probably part of its composition.

Strontianite is also the first type locality mineral species to have been described from Scotland.

It was not until 1807-1808, however, that Sir Humphrey Davy - well-known as the inventor of the miners' lamp - and who had previously isolated the elements sodium, potassium, barium, calcium and magnesium - managed, by similar techniques, to isolate the unknown element (strontium) from the new mineral species.

Strontian is also the type locality for the uncommon, zeolite mineral species - brewsterite (which also contains strontium).
The mineral is named for the Scottish physicist, Sir David Brewster, who invented the kaleidoscope and worked on polarized light.

Adair Crawford has been honoured in more recent years by the naming of the rare mineral species, crawfordite, for him.

First described from the Koashva Mine in the Kola Peninsula in Russia, crawfordite aptly contains the element strontium in its atomic structure. (for more on Adair Crawford, see below).

STRONTIANITE - Whitesmith Mine, Strontian, Argyll.
Clove brown radial crystal groups on creamy, cockscomb-habit barite.

Strontian's Minerals

The most impressive and typical specimens are from the Bellsgrove and Whitesmith Mines and, more recently, the Clashgorm Mine.

Between them, they have produced very good quality brewsterite and harmotome specimens - amongst the best for the species ever found anywhere - as well as calcite and, very occasionally, strontianite.

Recent Finds

In recent years, various forms of calcite and crystal groups of blocky harmotome crystals have been extracted. Harmotome has also been recovered as micro-crystals in a variety of twinning habits and galena and millerite specimens have also been found.

Additional minerals, previously not recorded at Strontian, include the rare strontium-bearing mineral, ancylite, as micro-crystals, kainosite - Y, and, more recently, the hydrous zinc and manganese oxide, woodruffite.

The zeolite mineral, heulandite, (the Strontium-bearing, Heulandite-Sr), uncommon to Strontian, was also found in 2008 as good crystals.

Location map of STRONTIAN

Collecting at Strontian.
(NB: Permission must be sought beforehand to collect at the site).

Strontium & Strontianite - Their Discoveries

Strontianite was "discovered" in 1790 by Adair Crawford and named after the locality. He recognized a new mineral, strontianite, (SrCO3, strontium carbonate) in samples of witherite (BaCO3, barium carbonate) and soon realized a new element was also in the composition of this mineral.

There is some debate concerning the early finds of strontianite. Leadhills and Wanlockhead - Scotland's premier mineral location - in its earlier mining days, saw an influx of miners from Strontian. (These miners on occasion settled there and current inhabitants from the Leadhills & Wanlockhead area may often have ties with the Argyll area where Strontian is located).

An early mineral collector, the Rev. Walker, noticed material (strontianite) in the hands of a group of such miners from Strontian in 1761. Three years later, in 1764, more material was "found". Mistaken for witherite, a dealer brought some of this to Edinburgh in 1787.

After examination by Adair Crawford, his proposal of a new element in the mineral's composition was confirmed by Dr. Hope (hopeite).

Strontianite at Strontian

The occurence of strontianite at Strontian, the type locality, is not a common occurence and when it is found, it is often as acicular or crystalline aggregates.

As well-developed, individual crystals, it is uncommon;
though, very occasionally, micro-crystals may be found typically as tapering, acicular crystals in sprays and balls.

The most recent finds of strontianite have been of a pale green colour and of the acicular habit. Brownish tones are also very typical at Strontian. In addition, previously unreported colour-zoned strontianite was found in 2007.

The mineral is vitreous and, apart from the fibrous/ acicular habits, it is also found in a massive form. The mineral is regularly found associated with massive barite or calcite.

Clove brown strontianite was found in early mining days and very limited finds occur nowadays of this material.

Strontianite from Strontian, the type locality, fluoresces in long wave, Ultra-Violet light with a bright lemon or pastel yellow colour.

STRONTIUM - The Element

Economic resources of strontium are almost exclusively obtained from the mineral, celestite, strontium sulphate.

Nevertheless, strontium carbonate is an important product obtained from the treatment of this ore and is widely distributed for use in industry.

Leading strontium-producing nations include Mexico, Spain and China.

Strontium is used in fireworks and flares, which render a crimson red light on burning. The use of strontium carbonate in the manufacture of television screens and tubes has helped maintain strontium production levels.

The element is also employed in refining zinc and most recently in medicine, for the treatment of osteoporosis.

The Strontium 90 isotope is radioactive and is produced by nuclear fall-out.

STRONTIANITE - for Collectors

Apart from Strontian, it has also been recorded at other Scottish localities, including Beith, Ayrshire and the Muirshiel Mine, Lochwinnoch, Renfrew. (see Glasgow area page).

Other sites of interest to collectors in the UK include the notable North Yorkshire occurences (Merryfield & Gunnerside Gill Mines). (see Pennines page).

Farther afield, Germany (Freiburg & St. Andreasburg) and Austria (Oberdorf und Laming) are classic sites for the species. The sulphur mines of Sicily in Italy also produced small crystals. In the USA, the Oak Hill area of Travis County in Texas and Northumberland County in Pennsylvania have also produced some good specimens.

However, perhaps the finest crystallized examples of recent years, most readily available to collectors worldwide, were the specimens from the fluorite deposits of the Rosiclaire area, Illinois, USA.

ADAIR CRAWFORD

Born in 1748, in County Antrim (now a county in Northern Ireland), Adair Crawford studied at Glasgow University and also researched in Edinburgh.

From 1777, he practiced as a doctor in Medicine in Edinburgh and in London.

It was in Edinburgh that he pointed out that material thought to be witherite (see above) had incompatible differences with this mineral species.

He further suggested that it may contain a new "earth" (chemical element). Three years later, in 1793, this was to be confirmed by Dr. Hope.

Adair Crawford, who received a knighthood, died in 1795, in Hampshire (England).

ACKNOWLEDGEMENTS:
This website wishes to thank Dr. Stephen Moreton for graciously supplying information regarding strontianite and its discovery.
Dave McCallum, Brian Jackson & Dave Green for the collecting & location photos of Strontian and its mines;
and to Eddie Lynch for the explanation on the use of barite for the North Sea oil & gas industries.

References/ Further Reading

UKJMM - (United Kingdom Journal of Mines & Minerals)
no.7; p. 12. & no. 19; p.6.
vol. 21; pp 8-27. "Twenty Years in Minerals: Scotland." (D. I. Green/ J.G. Todd) (2001).
vol. 29: p.15; Mineral News (Scotland); M.Wolfe, M. Oddy, R. Starkey. (2008).
Mineralogical Record
vol. 12,4, p.250. Leadhills & Wanlockhead - (RJ Gillanders) (1980).
Minerals of Scotland - (NMS Publishing) A. Livingstone. (2003).