Rock 365 : Day 9 : Blue John #365photos


Day 9 : From the back garden collection – Blue John, the purple variety of fluorspar (calcium fluoride). The name is derived from the French 'bleu et jaune" which decribes the colours found. This sample was collected near Castleton on one of my first ever geology field courses, to the Peak District as an A level student.


~ by hypocentre on January 9, 2010.

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