JouravskiteThis lovely lemony yellow crust and crystal is a rare calcium manganese sulphate mineral.

JouravskiteThis lovely lemony yellow crust and crystal is a rare calcium manganese sulphate mineral. It was only named in 1965 after the chief geologist of the Moroccan Geological Survey, where it was first discovered. Colour varies from green through orange to yellow, and its extreme softeness (2.5 on Mohs scale) means that specimens should be treated with great care due to their delicate nature.It forms in oxidised zones of polymetallic metal deposits rich in manganese, where oxidised groundwaters percolating through the ore body have turned the primary reduced minerals into secondary ones (see http://bit.ly/1I4XWKt for an explanation of the process). This 1.8 x 0.8 x 0.7 cm crystal and 2.6 x 1.9 x 1.9 cm crust on matrix were both mined at N'Chwanning in South Africa’s Kalahari Manganese Field.LozImage credit: Rob Lavinsky/iRocks.comhttp://www.mindat.org/min-2118.htmlhttp://bit.ly/28O3XBjhttp://bit.ly/28QBhwc -- source link

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