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Uploaded on:
11/03/2009 05:37:59
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120.78 KB
1001 x 678 pixels
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P number: P521529
Caption: Mineral specimen of calcite from amygdale. Dunure Railway, Brown Carrick Hills, Ayrshire.
Description: The photograph shows two mineral fragments from an amygdale, dominated by white calcite forming large crystal rhombs, and a fine-grained blue-green material termed 'green earth'. British Geological Survey Petrology Collection sample number E 3308A. Green earth is a name used to describe any of various naturally occurring silicates (probably mainly of iron) which have been used as bases for green dyes and pigments. Specific minerals are glauconite and caladonite. Amygdales are common in the Old Red Sandstone (Devonian) lavas of the Carrick Hills. This specimen is filled with calcite associated with 'green earth' a green earthy mineral of undetermined composition. As well as containing amygdales, the lavas are often brecciated and the fragments cemented by calcite. Occasionally veins of quartz, chalcedony or calcite cut the lavas. The specimen was presented by John Smith, the author of the book 'Semi-precious stones of Carrick' (1910).
Date taken: 01/01/2003
Photographer: Unknown
Copyright statement: NERC
Orientation: Landscape
Size: 120.78 KB; 1001 x 678 pixels; 85 x 57 mm (print at 300 DPI); 265 x 179 mm (screen at 96 DPI);
Average Rating: Not yet rated
Categories: Best of BGS Images/ Rocks and minerals  


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