Mawbyite

Mawbyite is a lead iron zinc arsenate that was named in honor of Maurice Alan Edgar Mawby. It has been approved by the IMA in 1988, and was published just a year after being described by Pring. Mawbyite is a member of the tsumcorite group, the monoclinic dimorph of carminite. It was first believed to be tsumcorite; however, crystal-structure determination showed iron and zinc occupying the same crystallographic site instead, and through the analysis it turned out mawbyite is isostructural with tsumcorite, meaning the two share a similar formula. More accurately, mawbyite appears to be the ferric analogue of the aforementioned mineral. The relationship between helmutwinklerite – which shares a similar formula with tsumcorite's – and mawbyite had been suggested, but due to lack of data it remains unclear. A full crystal-structure analysis is required in order to understand the relationship between their structures.