Representative rock sample for the manganese mineralization contained in the cherts of Val Graveglia (Genova), siliceous sedimentary rocks in which quartz is the fundamental component. Some levels are bioclastic accumulations of radiolarian shells, siliceous shelled organisms that thrived on the deep seabed in the Malm (Late Jurassic), from 163.5 to 145 million years ago (mya). This sample comes from the mine of Gambatesa.
Sedimentary levels of jasper are observed alternating with black levels that enclose the manganese mineral. The main mineral extracted from these levels is braunite, a manganese silicate which contains up to approximately 60% of this element Mn++Mn+++6SiO12.
This rock sample belongs to the DISTAV collections of the University of Genoa.
This model was realized by Glenda Cantale during the Universal Civil Service (SCU) at the Genoa University
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