Schist, Garnet mica, Glenborrodale Scotland.

This is a thin section of a Garnet Schist from Glenborrodale on the Ardnamurchan peninsular. Moine Schists form the bedrock underlying the volcanic rocks. This sample is a remarkably clear and interesting example. Mineralogy is what you would expect, Muscovite and Biotite micas, chlorite, recrystalised quartz and garnets, which are particularly interesting as they contain 3 zones and significant internal texture, including evidence of rotation during growth. Clear, colourful and unusual. Recommended.


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Essexite. Crawfordjohn, Scotland

This is a thin section of a rare volcanic rock, Essexite. From Crawfordjohn in southern Scotland. A silica poor rock containing large titaniferous (pink) augite crystals with excellent crystal form, showing growth zoning, zoned inclusions, sector zoning and magnificent interference colours. Numerous small but colourful olivine, somewhat fuzzy labradorite laths rimmed with alkali feldspar; apatite and magnetite. See page 97 Atlas of Igneous rocks and their textures. Very Special.


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Chrysocolla, Arizona, USA.

This is a thin section of Chrysocolla with sometimes Malachite, copper ore, from Arizona USA. Banded botryoidal texture showing beautiful growth patterns.  Also some good bands iron mineral at edge (?goetheite) Good material, highly recommended. Some bubbles in the cement in this slide.


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Dolerite (Scourie Dyke). Lewisian. Scotland.

This is a thin section microscope slide of Scourie Dyke material from Scourie, North West Highlands of Scotland. Thought to be 2390 million years old, (give or take a year or two), cutting even more ancient Lewisian Gneiss, and getting on for half the age of planet earth. Some of the most ancient rocks found anywhere. The Scourie Dykes are world famous. Essentially a dolerite, containing plagioclase, remarkably unaltered, nicely twinned and zoned, some showing curving due to subsequent strain, pyroxene and magnetite both rimmed with hornblende, and a little quartz. Essential part of any serious collection.



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Stromatolite. Bolivia.

This is a thin section microscope slide of a fossilised stromatolite from the Bolivia, 2.2 to 2.4 Billion Years old. Shows growth banding and oolites. Excellent example.


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Actinolite in Talc. N.W. Scotland

This is a thin Section microscope slide of a rock from Auctertyre, near Kyle of Lochalsh, associated with the Lewisian (pre cambrian) 'inlier'. Well formed crystals of actinolite in a matrix of very fine grained talc. Very pretty in XPL.


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