| P number: | P528027 |
|---|---|
| Caption: | Photomicrograph of colomite. Light: XPL. Magnification: x2.5. Old quarry 430 yards east 14 degrees south of Sheildaig Lodge, Gairloch, Rossshire, Scotland. |
| Description: | A white coarsely crystalline dolomite containing scales of pale brown mica. This specimen is Lewisian (Precambrian) in age. BGS sample number SL 261. British Geological Survey Petrology Collection sample number S 35268. Photomicrograph details: Light: XPL, Magnification: x2.5. The rock is composed of interlocking grains of carbonate up to 15 mm long and usually slightly elongated in the direction of foliation as shown by the mica flakes. These are abundant, colourless, almost uniaxial highly birefringent phlogopite. Quartz is an abundant accessory or subordinate constituent and is arranged in lenticular groups of elongated twinned grains in which all the directions of elongation are parallel to the foliation. Colourless tourmaline is an abundant accessory, in stout prisms with rounded terminations, up to 0.5 mm long. The carbonate is locally slightly granulitized. In summary the rock is a dolomite with phlogopite and quartz. It is medium-grained, with a foliated texture. |
| Date taken: | 25/06/1905 |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 320.32 KB; 1000 x 663 pixels; 85 x 56 mm (print at 300 DPI); 265 x 175 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Unsorted Images |
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