Garnet and is one of the most prized of garnet varieties. Topazolite is a golden-yellow variety and melanite is a black variety. Grossular is a calcium-aluminium garnet with the formula CaAl(SiO), though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, "grossularia", in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Because of its inferior hardness to zircon, which the yellow crystals resemble, they have also
Gemstone irradiation Gemstone irradiation The gemstone irradiation is a process in which a gemstone is artificially irradiated in order to enhance its optical properties. High levels of ionizing radiation can change the atomic structure of the gemstone's crystal lattice, which in turn alters the optical properties within it. As a result, the gemstone's color may be significantly altered or the visibility of its inclusions may be lessened. The process, widely practised in jewelry industry, is done in either a nuclear reactor for neutron bombardment, a particle accelerator for electron bombardment, or a gamma ray facility using the radioactive isotope cobalt-60. Irradiation has