Sunstone Gem: A very hot Colored Gemstone

Sunstone Gem

A Hot Feldspar

The Sunstone is a member of the Feldspar group. The large group of Feldspar also includes Amazonite, Labradorite displaying optical phenomena and Labradorite not displaying optical phenomena. If Labradorite Feldspar presents Aventurescence is a Sunstone. Aventurescence is the optical phenomenon that produces the shimmering effect (Glittering Effect) on the surface of some Gemstones. When a Sunstone is tilted and rocked, the inclusions of Copper and Hematite reflect back the light, spreading golden glow throughout the Gem.

Another Gemstone belonging to the Feldspar group is the the Moonstone. Although Moonstone and Sunstone both belong to the Feldspar group, they are Gemstones very different each other. While the cold Moonstone gives us a sweet and subtle adularescent glow, the warm Sunstone exhibits a lively and distinct aventurescent shimmer.


We are used to seeing the Sunstone exhibit the typical pink, red and orange colors. But the Susntone can also appear in nature with other colors. In fact, there are green and even bi-colored Sunstone (green and red), but they are extremely rare.

Copper inclusions produce the famous “Schiller effect” on the Sunstone Gem surface. The Schiller Effect creates a luster at the same time shimmering and metallic. Oregon’s Sunstone is currently having a great success. In fact they show a remarkable beauty and are also natural and untreated.


Sunstone Gem: Potassium or Calcium Feldspar?

The Feldspar group has many members. It can be divided into two broad categories: Feldspars which contain Potassium and Feldspars which contain Sodium and Calcium.

Orthoclase, which includes Precious Gems such as Moonstone, Amazonite and Sunstone, contains Potassium.
Plagioclase, which includes Labradorite and Oligoclase, is instead a mixture of Calcium and Sodium. Both the species of Feldspar Ortoclase, and that of Feldspar Plagioclase can give birth to the Sunstone variety.

The Labradorite Refractive Index is 1,559-1,568.
The Labradorite Specific Gravity is about 2.70.

Gems from Oregon can show a remarkable red and green pleochroism. In fact, they appear green when viewed in one direction and appear totally red when viewed in the opposite direction.

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