The above photo is a hand specimen of dolomite with a greenish variety of muscovite, known as fuchsite. The muscovite is high in chromium where chromium replaces aluminium in the crystal structure.
It is named after Johann Nepomuk von Fuchs, (1774-1856) chemist and mineralogist; Mattenzell, near Bremberg, Lower Bavaria. The specimen, from Brian Young, is from the base of the Ben Lui Schist, Creag Bhocan, Tyndrum, Perthshire grid ref. NN307278

The photo above right is a thin section of the same rock scanned with crossed polars. It shows the very high birefringence of dolomite, almost white, as well as the typical rhombohedral twin lamellae seen towards the bottom right.

The bright interference colours of fuchsite are visible on the left.

For further information on fuchsite cf. cf.

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