Sunstone
| Sunstone | |
|---|---|
| General | |
| Category | Tectosilicate minerals |
| Group | Feldspar group |
| Series | Alkali feldspar series |
| Formula | (Ca,Na)((Al,Si)2Si2O8) |
| IMA status | Variety of microcline or oligoclase |
| Crystal system | Triclinic |
| Identification | |
| Color | Colorless, orange, yellow, red, green, blue, brown, and copper shiller |
| Crystal habit | Euhedral crystals, granular |
| Twinning | Lamellar |
| Cleavage | 001 |
| Mohs scale hardness | 6.0–6.5 |
| Diaphaneity | Transparent to translucent and opaque |
| Specific gravity | 2.64–2.66 |
| Refractive index | 1.525–1.58 |
Sunstone is a microcline or oligoclase feldspar, which when viewed from certain directions exhibits a spangled appearance. It has been found in Southern Norway, Sweden, various localities in the United States, and on some beaches along the midcoast of South Australia.