Rock 365 : Day 6 : Larvikite #365photos

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Day 6 : The second deskcrop from my collection is Larvikite, from the Norwegian town of Larvik. Larvikite is technically a monazite, an intermediate igneous intrusive rock composed of approximately equal amounts of plagioclase and orthoclase feldspars with minor amounts of hornblende and biotite. The feldspars form a perthite texture, exsolving into alternating alkali feldspar and plagioclase lamellae giving a characteristic Schiller effect. This silver-blue sheen makes it popular for cladding banks in the UK, this specimen was rescued from a skip outside a bank undergoing a refurbishment in St Mary’s Street, Cardiff.

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~ by hypocentre on January 6, 2010.

 
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