Epidote

As a fissure mineral, epidote occurs mainly in alkaline rocks, but is not absent in acidic, granitic stone, where the crystals reach only a modest size. In alpine fissures (mainly in the Aar Massif), epidote is one of the first mineral types to be precipitated, which is why it is often found intergrown with quartz. The colour often appears brownish, but in backlight it turns a beautiful bottle green.

Photo: Epidote on quartz, Krummrück, Lötschental VS, collection Felix Spahr; not for sale.