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specimen
Details
ColorsBlack, Brown, Grey
Origin
SizeMedium
Dimensions9.2 x 6.2 x 5.6 cm
Species
Description

The trash-can mineral family: Tourmaline.

What species is this? Dravite? Schorl? Foitite?

Yes.

The entire family forms a wacky solid solution series with over 30 different species as "end-members". In reality, you never get a pure end member. Plus it is far from uncommon to get multiple in one crystal. Here we have a good example of this: the black radial sprays of tourmaline that come out of the Obira mine in Japan have a composition that is altering between Dravite, Schorl, and Foitite.

Obira Mine, Bungo-Ono City,

Oita Prefecture, Japan

Origin