grossulargarnet

Grossular is a calcium aluminum silicate mineral within the garnet group. Its chemical formula is Ca3Al2(SiO4)3. Grossular is the endmember of the grossular-hydrogrossular solid solution series. It is typically found in metamorphic rocks such as marbles and schists, and also in some igneous rocks. Grossular is known for its wide range of colors, which can include green, yellow, brown, orange, red, and colorless. The color is often due to trace impurities, such as iron, manganese, or chromium. Green grossular, especially when colored by chromium, is known as uvarovite, though uvarovite is technically a distinct mineral with a chromium endmember. Yellow to orange-brown grossular is often called hessonite. Grossular can form distinct crystals, often dodecahedrons or trapezohedrons, though it is also found in massive or granular forms. It has a relatively high hardness, typically between 6.5 and 7.5 on the Mohs scale, and a specific gravity of around 3.5 to 3.6. While not as commonly used in jewelry as some other garnet varieties, grossular, particularly hessonite and some green varieties, can be faceted and used as gemstones. Its metamorphic origins often link it to occurrences of other metamorphic minerals.