| P number: | P521327 |
|---|---|
| Caption: | Rock specimen of granite. Roger Law, Potrail Water, near Durisdeer, Lanarkshire, Scotland. |
| Description: | The sample is a altered coarse-grained granitic rock with pale-coloured feldspar and quartz, and finer grained muscovite white mica. Abundant rusty-orange coloured specks are caused by alteration of an iron-rich mineral, probably biotite, which has been replaced by fine-grained iron oxides. British Geological Survey Petrology Collection sample number EMC2870. Iron oxide can occur as a number of different minerals. Hematite (Fe2O3) is one of the most important minerals, forming a red to black or sometimes steel-grey colour. Limonite is a hydrated iron oxide with a black, yellow, brown or reddish colour. One of the smaller Caledonian plutonic intrusions found in the Southern Uplands. It is probably Devonian in age. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC2870 |
| Orientation: | Landscape |
| Size: | 295.36 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/ Geological structures |
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