Category
page 1Minerals in space group 192

beryl

sugilite
Sugilite ( ) is a relatively rare pink to purple cyclosilicate mineral with the complex chemical formula KNa2(Fe, Mn, Al)2Li3Si12O30. Sugilite crystallizes in the hexagonal system with prismatic crystals. The crystals are rarely found and the form is usually massive. It has a Mohs hardness of 5.5–6.5 and a specific gravity of 2.75–2.80. It is mostly translucent.
Sugilite was first described in 1944 by the Japanese petrologist Ken-ichi Sugi (1901–1948) for an occurrence on Iwagi Islet, Japan, where it is found in an aegirine syenite intrusive stock. It is found in a similar environment at
osumilite
Osumilite is a very rare potassium-sodium-iron-magnesium-aluminium silicate mineral. Osumilite is part of the milarite group (also known as the milarite-osumilite group) of cyclosilicates.
poudretteite
Poudretteite is an extremely rare mineral and gemstone that was first discovered as minute crystals in Mont St. Hilaire, Quebec, Canada, during the 1960s. The mineral was named for the Poudrette family because they operated a quarry in the Mont St. Hilaire area where poudretteite was originally found, and the quarry is currently owned by the United Kingdom based Salmon Mining Industries Inc. Poudretteite has a barely detectable radioactivity.
yagiite
Yagiite is a cyclosilicate mineral belonging to the osumilite group. It was discovered in 1968 in the iron meteorite that fell in Colomera in the province of Granada (Spain). Named after the Japanese mineralogist Kenzo Yagi, its CAS Registry Number is IMA1968-020.