itoite

Itoite is considered a questionable mineral at Tsumeb despite its type locality status.

During the study and description of fleischerite (Frondel and Strunz 1960) a second phase was noted that appeared to be pseudomorphous after fleischerite, with a very similar composition but with lower hydroxyl (OH^-) content. Itoite was described in the same paper as fleischerite (Frondel and Strunz 1960) but it has "special project" status (dated 1962) on the IMA mineral list (http://cnmnc.units.it/; accessed January 2023). Itoite was named to honour Tei-ichi Ito (1898-1980), professor of mineralogy at Tokyo University. Type material is conserved at the Institut für Mineralogie und Kristallographie, Technische Universität, Berlin (catalogue number 57/1405).

The itoite type material is from the first oxidation zone and is believed to have originated from between 6 and 8 levels. According to Frondel and Strunz (1960) itoite occurs as pseudomorphous white crusts of tiny acicular crystals that are individually colourless. Associated minerals are fleischerite, mimetite and plumbojarosite.

The status of itoite as a naturally occurring mineral at Tsumeb is, however, questionable.

Itoite has an almost identical PXRD pattern to fleischerite when the latter is heated to 300 degrees Celsius. According to the IMA, itoite remains an approved species but its validity as a naturally occurring mineral has been questioned. It is probable that 'itoite' is formed from fleischerite during preparation (grinding) for analysis.

For this reason, questionable status is retained for itoite, despite its type locality status.

cerussite (?); fleischerite (?); mimetite (?); plumbojarosite (?)