Grossular, Ca3Al2(SiO4)3 is a calcium-aluminium species of the garnet group. The colour of grossular is very variable, dark green, pink, brown, even colourless, and it's crystal classification is cubic, although most crystals are hexoctahedral. The specimen is from Grova in Southern Norway, an area known for copper mining. The crystals are cubic, and a very dark brown. They have slightly bevelled edges, and there is a quartz infilling of a fracture which runs through some of the crystals.