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Orange Sunstone
TRICLINIC

Sunstone

Microcline: KAlSi3O8
Oligoclase: (Na,Ca)Al1-2Si3-2O8

Hardness
6–6.5
Refractive Index
1.525–1.548
Spec. Gravity
2.62–2.65
System
Triclinic
Sunstone is an interesting feldspar gemstone with a glittery appearance and usually an orange or reddish color, hence its name. The glitter effect is caused by inclusions of the mineral Hematite, or sometimes also Goethite or Pyrite (and in one rare instance, Copper). The term used to describe the glittery effect exhibited on Sunstone is aventurescence.

About

Sunstone is very similar in habit to Aventurine, a form of Quartz that exhibits the same glittering Aventurescence effect. Sunstone is occasionally called 'Aventurine Feldspar' to distinguish it from its Quartz counterpart. However, Sunstone is always an orange or reddish color, whereas Aventurine, while sometimes occurring as orange or red, is most often green.

The glitter effect on Sunstone is usually red, orange, or golden yellow. It may also be green or blue, but this is very rare. Sunstone sometimes displays asterism in the form of four-rayed stars, and these stones are known as Star Sunstone. Sunstone occassionally also displays a cat's eye effect.

Uses

Sunstone that is opaque is cut into cabochons or polished into beads, and is used for necklaces, bracelets, and ornamental objects. The transparent forms of Sunstone or faceted into gemstone cuts for jewelry such as rings, earrings, bracelets, etc.

Varieties

✓ common  · ✗ uncommon

Treatments & Enhancements

Sunstone gemstones are not treated or enhanced.

Sources

Sunstone sources are in India, Norway, Russia, Madagascar and the United States (Oregon).

Similar Gemstones

Sunstone may closely resemble orange Aventurine, but Aventurine is slightly harder and is rare in colors other then green.

Further Reading

Faceted

In the Rough