silicates
Sunstone
- Also known as
- helioliteaventurine feldsparOregon sunstone
- Crystal system
- triclinic
- Hardness
- 6–6.5 on the Mohs scale
- Lustre
- vitreous
- Colour
- Orange to red-brown with a metallic glitter
- Where it forms
- In basalt flows and in pegmatites. The Oregon material crystallised in lava and carries native copper platelets, which is geologically unusual.
- Chiefly from
- Oregon, United StatesNorwayIndiaTanzania
Why it is that colour
Aventurescence, from tiny plate-like inclusions of copper or of hematite and goethite, aligned along planes in the feldspar and reflecting light together.
Safety
No hazard from handling.
Where it comes from
Oregon sunstone is mined on public and private claims in Lake County under US regulation and is unusually traceable for a gem. A large volume of copper-bearing red feldspar sold as sunstone from other sources has been shown to be artificially diffused with copper, and this was a significant gemmological scandal in the 2000s.
Historical use
A minor ornamental stone historically. Oregon sunstone is the state gem of Oregon.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
What is attributed to it, and since when
Some Norse and medieval Scandinavian sources refer to a solarsteinn used for navigation, and it is sometimes claimed to be this stone. The better candidate is Iceland spar, a calcite that genuinely polarises light and could locate the sun through cloud. Sunstone in the modern sense carries no old attribution; its meanings are recent.
Described, not endorsed. Dating a claim is not the same as assessing it — but an association that first appears in a book published in 1985 is not an ancient inheritance, whatever the label says. A sincere account of feeling better is compatible with the stone doing nothing — see the placebo effect.
Sold as this, but not
Worth knowing
The Viking sunstone story is a good example of a claim that is half true and gets reported whole. Norse sources do describe a stone used to find the sun in poor visibility, and the physics works — but with Iceland spar, a transparent calcite that splits light into two polarised rays and can be used to locate the sun through overcast. A calcite crystal was recovered from an Elizabethan shipwreck in 2013 and tested for exactly this.
That has nothing to do with the orange feldspar sold today as sunstone. Two different stones, one story, and the interesting version belongs to the one nobody is selling.
Identity checked against IMA-CNMNC master list, June 2025.