Abstract:
The article describes 6 types of gemstones which show phenomena such as chatoyancy and asterism. The gemstones have not been described before,either because they come from new sources,or because the phenomenon has not been seen before in the type of gemstone described. Gems from the new sources are star garnet from the Karelia Province in Russia,and star garnet from the Jiangsu Province in China.Grandidierite usually does not show a cat's eye effect,but the two described samples display a weak cat's eye. An unusual white quartz from Brazil with a sharp cat's eye is described,as well as a star sapphire with two differently coloured stars on each side of the cabochon,as well as a trapiche-type quartz. The stones were tested with gemmological,microscopic,and advanced techniques and the results are presented.