Anorthite (old classic)

Item Description

Anorthite is the calcium-rich end member of the albite-anorthite feldspar series. This old-time thumbnail is from a classic Japanese locality - Miyake Island and is a floater cluster of sharp, grayish-white anorthite crystals partially coated with a film of brownish glassy lava. Miyake Island is a small island with an active volcano and is famous as the classic locality for anorthite crystals, thousands of which were thrown out loose by the 1870 eruption and distributed in collections around the world (MINDAT). A trivial bit of edge wear reveals the glassy, colorless nature of the complete all-around and nifty thumbnail. From a major rarities collection.