Shigaite bookletThe growth layers as each thin tabular crystal precipitated from the mother ichor ar
Shigaite bookletThe growth layers as each thin tabular crystal precipitated from the mother ichor are clearly visible in this lovely example of a complex manganese (the source of the absorption that gives us the residual reddish brown, yellow or orange colour) containing sulphate mineral. Named after its type locality after its discovery in 1985 (the Shiga prefecture of Japan), this 2cm cluster is about as big as they get. It forms when manganese ore deposits are metamorphosed during their journey through geological time, such as those of the Kalahari manganese fields in South Africa, including a famed fount of many rare mineral specimens: the N'Chwaning Mine, where this 1.9 x 1.4 x 1.0 cm beauty hails from.LozImage credit: Rob Lavinsky/iRocks.comhttp://www.mindat.org/min-3638.html -- source link
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