Milarite, Adularia (Var: Valencianite)
Valenciana Mine, Guanajuato, Mun. de Guanajuato, Guanajuato, Mexico
Cabinet, 14.5 x 12.2 x 4.0 cm
The milarite crystals here, hexagonal crystals topped with flat yellow terminations, measure up to 6 mm across. Their size for this locality is pretty good, but it is the richness and overall size of the specimen that makes the piece significant. Such pieces are few and far between, and quite old. Another such is illustrated in the Bancroft book, Gem and Crystal Treasures, from the mid-1980s. These Mexican pieces are unique for their association with beautiful contrasting crystallized matrix of porcelain-like adularia feldspar, referred to as valencianite until recently. Ex. Martin Zinn Collection.