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P521538

Uploaded on:
11/03/2009 05:41:21
Type:
Digital Asset
File Size:
194.89 KB
Dimensions:
1000 x 775 pixels
5439 views 5 downloads
P number: P521538
Caption: Mineral specimen of thomsonite with analcime. North-west end of Loanhead Quarry, c. 2 miles north-north-east of Beith Station, Ayrshire.
Description: The specimen shows both thompsonite and analcime growing together in a cavity in altered basaltic rock. British Geological Survey Petrology Mineral Collection sample number 34376. Thompsonite typically occurs as radiating aggregates of striated crystals with an acicular (needle-like) or bladed habit. They are commonly colourless with a transparent or translucent appearance. The analcime (also known as analcite) occurs as well-formed white crystals in its typical form of trapezohedrons or modified cubes. Thomsonite is a hydrated sodium calcium aluminium silicate. It belongs to the zeolite group of silicate minerals and occurs in cavities in basalts. Thomsonite is recorded in Heddle's Mineralogy of Scotland as coming from Boylston Quarry, Loanhead in Renfrewshire. At this locality it is associated with analcime, rubinglimmer, yellow prehnite and rare forms of calcite. Analcime is a very common mineral found in the Tertiary basalt lavas throughout the British Tertiary Volcanic Province and is a hydrated sodium aluminium silicate.
Date taken: 01/01/2003
Photographer: Unknown
Copyright statement: NERC
Orientation: Landscape
Size: 194.89 KB; 1000 x 775 pixels; 85 x 66 mm (print at 300 DPI); 265 x 205 mm (screen at 96 DPI);
Average Rating: Not yet rated
Categories: Best of BGS Images/ Rocks and minerals  

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