A specimen of a double terminated, calcite scalenohedron crystal from Jebel Saghro, Morocco. Calcite is one of the polymorphs of calcium carbonate, the others being aragonite and vaterite. Calcite is one of the index minerals in the Mohs scale at number 3, as it is a fairly soft mineral, able to be scratched by your finger nail. As expected of this group of minerals, it reacts with hydrochloric acid or vinegar to release bubbles of CO2, this causes a reactions which results in bubbling and fizzing on the surface of the specimen. This sample of calcite has formed as a scalenohedron with double termination, most of the specimen is crystalline but a quarter of the piece is a impure non-crystalline form of calcite. The sample weighs roughly 47 grams and measures approximately 5.5 x 3.2 x 2.6 cm. This specimen is supplied in a white 3" x 2" card tray with an information label and is a must have for any mineral collection.