Description

Here, montroydite (red) is combined with pyrite and partially covers the crystals.
This piece comes from Monte Amiata, a large volcanic cone in the Apennines known for its cinnabar-rich rocks, straddling the provinces of Grosseto and Siena, on the edge of Tuscany.
Cinnabar is the mineral form of mercury oxide, with the chemical formula HgO.

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