| Schäferite | |
| Category: | Phosphate mineral Berzeliite group Garnet structural group |
| Strunz: | 8.AC.25 |
| Formula: | Ca2NaMg2[VO<sub>4</sub>]3 |
| Imasymbol: | Sfr[1] |
| Molweight: | 496.57 g/mol |
| System: | Cubic |
| Class: | Hexoctahedral (mm) H-M symbol: (4/m 2/m) |
| Symmetry: | Ia3d |
| Unit Cell: | a = 12.427 Å, Z = 8 |
| Color: | Red, orange-red |
| Habit: | Octahedral crystals |
| Cleavage: | None |
| Fracture: | Conchoidal |
| Mohs: | 5 |
| Luster: | Vitreous |
| Refractive: | n = 1.96 |
| Opticalprop: | Isotropic |
| Streak: | Yellow |
| Diaphaneity: | Transparent |
| References: | [2] [3] |
Schäferite is a rare vanadate mineral with chemical formula Ca2NaMg2[VO<sub>4</sub>]3. Schäferite is isometric, which means that it has three axes of equal length and 90° angles between the axes.[4] Schäferite is isotropic, meaning that the velocity of light is the same no matter which direction the light passes through.[3]
It was named after Helmut Schäfer (born 1931) who discovered it in a quarry on the Bellerberg Volcano in Germany.[2] It is found only in the Eifel Mountains volcanic area near Mayen, Laacher See district of Germany.[2] It occurs within a xenolith in a leucite tephrite. It is the magnesium analogue of palenzonaite and is a member of the garnet structural group.[3]