Mixite replacing Cafarsite (rare material)

Item Description

The most well known specimens of rare arsenate Cafarsite are found at the famous mountain of Scherbadung (German name) or Cervandone (Italian name), in the Binntal on the Swiss/Italian border of the Alps. The species got its name from this chemical composition (calcium, iron {Fe}, arsenate), but it turns out that the species has essential fluorine, so the chemical formula is going to be changed soon to reflect this. Additionally it appears that there is also sodium, manganese, aluminum and REE that will be part of the formula, so the species might have to be renamed to Canafemnaltiarsite. This is a nice piece of Cafarsite from the type locality, featuring a bronze colored, altered crystals which are being replaced by green Mixite on matrix. This is a very good representative specimen from this classic Alpine locality. Ex Kay Robertson Collection (#10713). Kay is a prominent California collector, who specialized in European classics (see the article in the March-April, 2007 Mineralogical Record and the 50+ page article in the German Magazine "Mineralien Welt" November-December 2017).