| P number: | P519682 |
|---|---|
| Caption: | Specimen of porphyrite from Furnace Quarry, Furnace, Argyllshire, Scotland |
| Description: | The rock is a polished slab of pink porphyry which has been used as decorative cladding on a building. The specimen is of Silurian/Devonian age. British Geological Survey Petrology Collection sample number EMC 5712. A porphyrite or porphyry is an intrusive igneous rock which contains phenocrysts, in this case of pink alkali feldspar. The pink groundmass of the rock indicates that it too is rich in minerals such as feldspar and also quartz. There is a wide range of feldspar types, split into two main compositional groups, plagioclase and alkali feldspar. The plagioclase series has chemical compositions that form a range from sodium to calcium rich crystals, whilst the alkali feldspars contain potassium. |
| Date taken: | Wed Jan 01 00:00:00 GMT 2003 |
| Photographer: | Bain, T.S. |
| Copyright statement: | NERC |
| Orientation: | Portrait |
| Size: | 189.12 KB; 775 x 1000 pixels; 66 x 85 mm (print at 300 DPI); 205 x 265 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Unsorted Images |
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