- Color: green, yellow, brown, orange, purple, blue
- Hardness: 6.5
- Refractive index: 1.67 - 1.76
- Density: 3.32 - 3.50
- Chemical composition: Ca10(Mg,Fe)2Al4(SiO4)5(Si2O7)2(OH)4
- Crystal structure: tetragonal
- Origins: Canada, USA, Italy, Russia, Switzerland, Tanzania, Kenya, Sri Lanka
Alternative name is vesuvianite. Rarely used in jewelry, the mineral is mostly interesting for collectors. Clean crystals over 5 ct. are rare. Unusual purple or blue varieties are the most expensive. Stones are generally not treated.