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Uploaded on:
11/03/2009 05:34:11
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P number: P521518
Caption: Mineral specimen of heulandite associated with white calcite. Loch Humphrey, Kilpatrick Hills, Dumbartonshire.
Description: The sample shows vivid orange-red crystals of heulandite with coarse white calcite crystals, within a dark altered basaltic rock. British Geological Survey Petrology Collection sample number E 3321A. Heulandite belongs to the zeolite minerals, and is a hydrated calcium aluminium silicate. It can vary in colour from colourless, white, greenish or yellowish. It is a secondary mineral formed by the hydrothermal alteration of basaltic rocks. The specimen is from a lava flow of Carboniferous age from the Kilpatrick Hills. This locality is one of the best known for heulandite in Scotland, where red crystals of up to 3 cm. long have been reported. 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: 206.60 KB; 1000 x 775 pixels; 85 x 66 mm (print at 300 DPI); 265 x 205 mm (screen at 96 DPI);
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Categories: Best of BGS Images/ Rocks and minerals  


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