BiotiteAbout this object
Biotite; black mica.
Biotite is a common rock-forming mineral present in most igneous and some metamorphic rocks. It is of the mica group of sheet silicate minerals. Typical of this group is a highly perfect cleavage (referring to the tendency of crystals to split along definite crystallographic structural planes), allowing separation into thin, flexible sheets. It is usually black to brown in colour, however weathered tiny crystals of biotite can appear golden yellow and sparkling, producing a 'fool's gold'. It was named after the French physicist Jean-Baptiste Biot who in 1816 researched the optical properties of mica, discovering many unique properties.
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Collection of Thames School of Mines, Heritage New Zealand Pouhere TaongaObject Type
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