Hydroxylherderite (ex Rolando Gioia Collection)

Item Description

From an older find for this famous gem district. I think most people would agree that the most desirable color for Herderite (more properly Hydroxylherderite) is purple. This piece features a predominant, very sharp, well-formed, lustrous, gemmy, euhedral, monoclinic crystal of purple Hydroxylherderite with minor bladed white Albite and greenish-yellow Muscovite. Interestingly enough, the underside the specimen is hollow, almost as if the piece has formed a "cast" after a preexisting mineral. A very attractive specimen of a gem crystal species that is not often found in well-formed examples with a rare color. Purple minerals are rare in general, and if you eliminate Amethyst all you have left for the most part is Fluorite, Scapolite, Spinel, Zoisite (Tanzanite) and uncommon species like Hydroxylherderite. From the collection of Rolando Gioia (a contributor to new definitive book on Brazilian minerals: "Minerais e Pedras Preciosas do Brasil").