DIRK WIERSMA / SCIENCE PHOTO LIBRARY DIRK WIERSMA / SCIENCE PHOTO LIBRARY
Dravite mineral. Dravite is a mineral belonging to the tourmaline group and forms series with elbaite and schorl. Like all tourmalines it is trigonal, often occurring dispersed in its host rock, but sometimes forming fairly well faceted crystals of the dark honey-brown colour seen here. This sample, from St Lawrence County in New York State, USA, is 18 centimetres across.
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