Mineralpedia Details for Teallite
Named for Jethro Justinian Harris Teall, who was the Director of the Geological Survey of Great Britian and Ireland. This hydrothermal mineral can be found in tin veins and can be a locally important tin ore mineral in some places. Found in only a few localities worldwide, a large number of specimens that have been identified as Teallite may actually be franckeite. Teallite is a flexible mineral and may even be somewhat malleable.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/teallite.pdf