Sunstone Properties, Facts and Photos

What is Sunstone?

Sunstone is a variety of feldspar that exhibits an optical phenomenon known as aventurescence.

Also known as aventurine feldspar, it's composed mainly of aluminium, silicon, and oxygen, with either sodium or potassium, depending on the feldspar type.

Tiny plate-like metallic inclusions of the minerals goethite or hematite give sunstone a 'glittery' appearance. Inclusions can occasionally be copper.

Sunstone that's heavily included is far more desirable.

Heliolite, which comes from the Greek words 'helios' meaning 'sun' and 'lithos' meaning 'stone,' was once used as an alternative name, but is now rarely used. 

Sunstone is one of the few gemstones whose colour is rarely enhanced. When being graded, the strength of the aventurescence is far more important than the stone's colour. 

On the Mohs scale of hardness, sunstone grades 6 to 6.5. Hardness should not be confused with toughness, which relates to a rock or mineral's resistance to cracking, breaking or chipping.  

Sunstone comes primarily from India, Canada, Norway, China, Russia, and the United States (particularly Oregon).

Sunstone Vs Goldstone

Goldstone is a man-made material also known as aventurine glass. It was once widely used to imitate natural sunstone, but nowadays, it's rare to see it used for this purpose.

In goldstone, light reflects off tiny specs of crystallised copper, which are added during production. The effect can be vaguely similar to the aventurescence in sunstone.

Most goldstone is produced in China. The material is not rare and should not be labelled as a gemstone.  

Article Photos

The sunstone at the top of our article is a licensed stock photo. The tumbled stones are from our collection.

The sunstone in the next photo is courtesy of James St. John.  

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Copper, hematite: Courtesy of Stan Celestian.