schultenite (w. thometzekite)

thometzekite

Colourless-white platy crystals of schultenite (to 8 mm) associated with pale bluish-green thometzekite.

Mark Feinglos acquired this specimen in a trade with the Natural History Museum in London. It is a fragment removed from the schultenite type specimen (BM.1926,205) which was purchased from Wilhelm Maucher in 1926. Maucher believed the white mineral to be lanarkite, but investigations by Spencer and Mountain (1926) led to the description of a new mineral which they named schultenite. For the original specimen, Spencer and Mountain (1926) noted that anglesite was a major constituent of the matrix and referred to the bluish-green mineral simply as "bayldonite" which, they noted, appeared partly pseudomorphous after azurite and mimetite. A reinvestigation of the NHM specimen has demonstrated that the "bayldonite" is in fact thometzekite (Mike Rumsey, pers. comm. 2015). The vintage of the specimen (1926) ties it firmly to the first oxidation zone and, while no record of location in the mine is preserved with the type specimen, Klein (1938) recounted that "...schultenite (mistaken at first for lanarkite)..." was encountered at a depth of 190 m, which is consistent with 7 Level.