Schäferite is a rare vanadate mineral with chemical formula Ca₂NaMg₂[VO₄]₃. Schäferite is isometric, which means that it has three axes of equal length and 90° angles between the axes. Schäferite belongs to the optical class Isotropic, meaning that the velocity of light is the same no matter which direction the light passes through.

It was named after Helmut Schäfer (b. 1931) who discovered it in a quarry on the Bellerberg volcano in Germany. It is a rare earth mineral that is found only in the Eifel Mountains volcanic area near Mayen

Mayen

Mayen is a town in the Mayen-Koblenz District of the Rhineland-Palatinate Federal State of Germany, in the eastern part of the Volcanic Eifel Region. As well as the main town, there are five further settlements which are part of Mayen, they are: Alzheim, Kürrenberg, Hausen-Betzing, Hausen and Nitztal...

, Laacher See

Laacher See

' or Laach Lake is a caldera lake and a potentially active volcano, in Rhineland-Palatinate, Germany, situated close to the cities of Koblenz , and Bonn , and closest to the towns Andernach , and Mayen . The caldera lake lies just 8 km from the river Rhine at Andernach...

 district of Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

. It occurs within a xenolith

Xenolith

A xenolith is a rock fragment which becomes enveloped in a larger rock during the latter's development and hardening. In geology, the term xenolith is almost exclusively used to describe inclusions in igneous rock during magma emplacement and eruption...

 in a leucite

Leucite

Leucite is a rock-forming mineral composed of potassium and aluminium tectosilicate K[AlSi2O6]. Crystals have the form of cubic icositetrahedra but, as first observed by Sir David Brewster in 1821, they are not optically isotropic, and are therefore pseudo-cubic. Goniometric measurements made by...

 tephrite

Tephrite

Tephrite is an igneous, volcanic rock, with aphanitic to porphyritic texture. Mineral assembly is usually abundant feldspathoids , plagioclase, and lesser alkali feldspar. Pyroxenes are common accessory minerals. Quartz and olivine are absent. Occurrences include phonolite-tephrite Mt...

. It is the magnesium analogue of palenzonaite and is a member of the garnet group

Garnet

The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. The name "garnet" may come from either the Middle English word gernet meaning 'dark red', or the Latin granatus , possibly a reference to the Punica granatum , a plant with red seeds...

.