Crystals of orthoclase with inclusions of biotite
Crystals of orthoclase with inclusions of biotite
Twinned crystal of orthoclase
Photographs are from the Geologists' Association 'Carreck Archive' held at the British Geological Survey.
Quartz-tourmaline rock or 'stent'
Photographs are from the Geologists' Association 'Carreck Archive' held at the British Geological Survey.
Posted by Bob McIntosh
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