Admontite

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Admontite is a hydrated magnesium borate mineral with the formula MgB6O10·7H2O. It occurs in gypsum deposits and is often found with gypsum, anhydrite, hexahydrite, löweite, eugsterite, pyrite, and quartz. It is named after Admont, Austria.

Key properties
- Color: colorless; streak: white
- Hardness: about 2–3 on the Mohs scale
- Density: ~1.84 g/cm3
- Cleavage: absent; Fracture: conchoidal
- Crystal system: monoclinic; space group P21/c
- Optical: biaxial negative; nα ≈ 1.442, nγ ≈ 1.504; birefringence ≈ 0.062; dispersion none
- Classification: Strunz 6.FA.15; Dana 26.6.3.1