CALCITE, PYRITE covered with BRAVOITE, QUARTZ, MMG MINE, ROSEBERY, TASMANIA

Calcite is a carbonate mineral and the most stable form of calcium carbonate (CaCO3). Calcite is widely present, particularly as a key element in limestone. Calcite has a hardness rating of 3 on the Mohs scale, and people assess it based on its ability to be scratched. Large crystals of calcite are utilized in optical devices, while limestone, primarily made up of calcite, serves a variety of purposes.

This specimen features pyrite (iron sulfide) with attractive superficially pyritohedrons similar to the ones found in the Wilmut tunnel. However, the crystals have a bravoite coating, which distinguishes this specimen from the one found in the other locality.

Bravoite is a sulfide mineral that contains a high amount of nickel and iron. Although scientists once classified bravoite under a specific formula, they now mainly view it as a nickel-rich variety of pyrite or part of the vaesite-cattierite series. This mineral is known for its unique, often striped coloration, which can be quite vibrant. It typically forms in low-temperature hydrothermal veins and in basic igneous rocks.