- Color: green, yellowish green
- Hardness: 6.5
- Refractive index: 1.88 - 1.89
- Density: 3.82 - 3.85
- Chemical composition: Ca3Fe2(SiO4)3
- Crystal structure: isometric
- Origins: Russia, Namibia, South Africa.
Demantoid is a rare and expensive green variety of garnet andradite. The best stones come from the Ural Mountains in Russia. Peculiar 'horse tail' inclusions of byssolite are appreciated by collectors, and will increase the stone's value. Demantoids are generally not treated.