The Crystal Tree

Beudantite is a difficult mineral to classify in that it has both an arsenate anion group and a sulfate anion group. The arsenate anion would normally dictate that beudantite be classified in the Arsenate Subclass of the Phosphate Class of minerals. But beudantite’s sulfate anion group is intricate and essential in its structure, while the arsenate anion group can be substituted for by a phosphate anion group to at least a limited degree (see the Beudantite Group below). Many classification schemes place beudantite in the Phosphate Class however. Beudantite, which is named for the French mineralogist Francois S. Beudant, is at times a very attractive mineral. It can be beautifully colored although often too dark, appearing black. It has a nice high luster due to its lead content. It is often associated with other rare secondary minerals that are found in the oxidation zone of ore deposits. Often these assorted mineral specimens can be quite interesting and a bonus to the collector who likes lots of different minerals on one specimen (more for the money, so to speak).