ReiSi2O6

ReiSi2O6, also known as rankinite, is a rare mineral compound. It has a chemical formula of Sr2Si2O6. The mineral is categorized under the group of rankinite and is a member of the fluorite group.

Rankinite is composed of strontium ions, silicon ions, and oxygen atoms. It is known for its rare occurrence in the Earth's crust. The mineral was first discovered in Germany and later found in other parts of the world, such as Russia and the United States.

ReiSi2O6 is typically found in hydrothermal veins within igneous and metamorphic rocks. It often forms in association with other minerals such as quartz, calcite, and pyrite. Its hardness ranges from 6 to 6.5 on the Mohs scale.

Rankinite has been of some interest to researchers due to its unique crystal structure and its mechanical properties. In the past, rankinite was also proposed as a possible host for Yb3+- cm Up conversion emission, which was studied for laser applications.

The name "rankinite" is derived from the German town of Rankweil, Austria, where the mineral was first discovered. Rankinite has a triclinic crystal system, and its optical properties include negative optical sign. It has been assigned the mineral number IMA1980-12 by the International Mineralogical Association.