Sunstone
What is Sunstone?

Sunstone is a member of the Feldspar family and is known for its spangled appearance, or sheen, caused by light interacting with tiny plate-like mineral inclusions within the stone. It’s primarily found in Norway, the United States, and India. Sunstone is often used as a gemstone and is a popular choice for jewelry due to its radiant, sun-like inclusions and spiritual significance.
Sunstone is a radiant gemstone known for its glittering, sun-like inclusions. Its warm hues and sparkling appearance make it a popular choice for jewelry and decorative items. The stone is often used in rings, necklaces, and pendants.
Chemical Classification | Inorganic - Silicate (Feldspar) |
Color | Ranges from orange to brownish-red, often with sparkling inclusions. |
Streak | White |
Luster | Vitreous to pearly. |
Transparency | Transparent to translucent. |
Occurrence | India, the United States (Oregon), and Norway. |
Formation | Sunstone forms in magmatic and pegmatitic rock, and can also be found in alluvial deposits. |
Diaphaneity | Transparent to translucent with aventurescence |
Cleavage | Perfect in one direction |
Mohs Hardness | 6 to 6.5. |
Specific Gravity | 2.63-2.67. |
Diagnostic Properties | Aventurescence (sparkling or metallic glitter). |
Chemical Composition | (Ca,Na)(Si,Al)4O8 |
Pleochroism | Weak to distinct, depending on the stone. |
Crystal System | Triclinic (variety of Feldspar) |
Optical Properties | Biaxial (+) |
Refractive Index | 1.525 - 1.548 |
Birefringence | 0.008 - 0.010 |
2V angle | Measured: 50° to 65° |
Dispersion | Not typically noted for sunstone as it's not a key feature of this stone. |