5ct freeform Sugilite with Pyrolusite rectangular cabochon . Size is 14.8 x 9.4 x 3.3 mm. Sugilite is a rare purple cyclosilicate mineral that was named after the Japanese petrologist, Ken-ichi Sugi, who first identified it in 1944 in Iwagi Islet, Japan. However, this occurred as brownish-yellow grains that were not suitable for use as gemstones. A significant deposit of gem-quality material was later discovered in 1979 at a manganese mine in the Southern Kalahari Desert of South Africa. In 1980 sugilite was officially classified as a rare gem, which caused its price to increase. Since then, additional deposits have been discovered, but since these are small, it remains a rare gem.