What makes sunstone sparkle?

Platy inclusions oriented along a crystal plane, catching light and throwing it back. In Oregon material those platelets are native copper; elsewhere they are usually hematite or goethite. The effect is called aventurescence, and Oregon sunstone is one of very few gems containing a metal in native metallic form.

Is goldstone the same thing?

No. Goldstone is manufactured glass with copper crystals grown in it, an Italian invention from around the seventeenth century. It sparkles far more uniformly than any mineral, and under a loupe the copper crystals are identically sized and evenly spread. It is attractive and cheap; the problem is only when it is sold as a stone.

Is Oregon sunstone treated?

Some is. Copper diffusion treatment emerged in the 2000s to intensify colour and must be disclosed. Treated stones often show colour concentrated near the surface and a distinctive distribution through the crown. Untreated Oregon material with strong colour and flash commands a premium.

Is sunstone the Viking sun-stone?

Almost certainly not. The solarsteinn mentioned in Icelandic sources as a navigational aid is thought to have been a birefringent or pleochroic crystal, with Iceland spar calcite, cordierite and tourmaline as the leading candidates. The name sunstone for this feldspar is a modern coincidence.

Is the sunstone and moonstone pairing traditional?

No, it is twentieth-century. Moonstone has a genuine Indian tradition as chandrakanta; sunstone has almost no ancient tradition at all. The pairing is a neat modern symmetry, which is worth recognising as such while still finding it useful.

← →

Feldspar & the feldspathoids · Orange & amber ray

Sunstone

Sunstone is feldspar containing microscopic platelets of copper or hematite that catch light and throw back a metallic glitter, an effect called aventurescence. The Oregon material, coloured and flashing from native copper, is the state gem and is one of the very few gems where copper occurs in metallic form inside the crystal.

At a glance

Feldspar with copper platelets suspended in it, flashing metallic orange when turned.

Composition: feldspar with copper platelets
Crystal system: Triclinic
Hardness: Mohs 6
Family: Feldspar & the feldspathoids
Colour ray: The orange ray
Main sources: Oregon, India, Norway, Russia, Tanzania
Care: Hardness 6 with cleavage. Safe in water, but chips easily.

Themes

warmth being seen the flash confidence daylight

What it actually is

Feldspar, in Oregon a plagioclase and elsewhere often an oligoclase or orthoclase, hardness 6, with two cleavage directions.

The glitter comes from platy inclusions oriented parallel to a crystal plane. In Oregon sunstone those platelets are native copper, and their concentration determines both the flash and the body colour, which runs from colourless through champagne to deep red and green. In Indian and Norwegian material the inclusions are usually hematite or goethite, producing a bronzy orange sparkle.

The effect is called aventurescence, and it is the same phenomenon that gives aventurine its name, which came from a Venetian glass rather than from either mineral.

Oregon sunstone is one of the few gems in which a metal occurs in native metallic form as an inclusion.

Where it comes from

The Ponderosa and Dust Devil mines in Lake County, Oregon, produce the copper-bearing material, which was designated the state gem in 1987. Some of it comes from public collecting areas where anyone may dig.

India produces large quantities of the hematite-included orange material that fills most of the tumbled and bead market.

Norway's Tvedestrand deposits are the historic European source, and Russia and Tanzania also produce material.

Sunstone appears in Viking-era discussion because of the solarsteinn, the sun-stone mentioned in Icelandic sources as a navigational aid; the leading candidates are Iceland spar calcite, cordierite and tourmaline rather than the stone we now call sunstone, so the name is a coincidence.

What the traditions claimed

Sunstone has little ancient tradition of its own. It was not a distinguished material in the classical or medieval worlds, and its name is modern.

The Norwegian and Greek material was known and used locally, and some sources associate sun-stones generally with solar symbolism, but that is a colour reading rather than a documented practice attached to this mineral.

The Oregon material carries a genuine contemporary significance, both as a state gem and through its place in the culture of public rockhounding, where anyone can dig their own.

Modern crystal practice reads sunstone as a stone of confidence, vitality and personal warmth, often paired with moonstone as a complementary opposite. That pairing is a twentieth-century invention and is a good example of how neat symmetries get built into the tradition after the fact.

How it is worked with

The confidence reading suits questions about visibility rather than courage: being comfortable being looked at, taking credit, occupying a room. That is a different problem from being afraid, and sunstone fits it better than a red stone would.

The moonstone pairing, though modern, is a usable structure: one stone for what is not yet decided and one for stepping forward once it is.

At hardness 6 with cleavage this is a pendant or pocket stone, not a working ring stone.

Oregon material is worth buying in person if you can, since the flash and the body colour vary enormously and photographs are taken at the best angle.

Clean with a soft cloth and lukewarm soapy water. No ultrasonic cleaners.

Buying it honestly

The main substitution is goldstone, a manufactured Venetian glass with copper crystals grown in it, invented around the seventeenth century. It sparkles far more uniformly and brightly than any mineral, and under a loupe the copper crystals are all the same size and evenly distributed. It is a lovely material sold dishonestly.

Some Oregon sunstone is diffusion-treated with copper to intensify colour, a practice that emerged in the 2000s and that must be disclosed. Treated stones often show colour concentrated at the surface and a distinctive colour distribution in the crown.

Indian orange sunstone is genuine and much cheaper than Oregon material, and the two are sometimes conflated.

Dyed and coated feldspar appears at the very low end.

Handle with care

Hardness 6 with two cleavage directions: chips and splits under impact. No ultrasonic cleaning. Otherwise safe in water and in sunlight.

أسئلة للتأمل

What am I doing that I would rather nobody noticed, and why?
Is my discomfort about being seen, or about not being ready to be seen?
Where would taking credit change what happens next?

Follow the thread

🌈

Moonstone

The modern complementary pairing

🟠

Carnelian

The other stone of warmth and craft

🌈

Labradorite

The same family with a different optical effect

🪨

Feldspar & the feldspathoids

The family this stone belongs to

🟠

The orange ray

The ray it carries

Frequently asked questions

: Platy inclusions oriented along a crystal plane, catching light and throwing it back. In Oregon material those platelets are native copper; elsewhere they are usually hematite or goethite. The effect is called aventurescence, and Oregon sunstone is one of very few gems containing a metal in native metallic form.
: No. Goldstone is manufactured glass with copper crystals grown in it, an Italian invention from around the seventeenth century. It sparkles far more uniformly than any mineral, and under a loupe the copper crystals are identically sized and evenly spread. It is attractive and cheap; the problem is only when it is sold as a stone.
: Some is. Copper diffusion treatment emerged in the 2000s to intensify colour and must be disclosed. Treated stones often show colour concentrated near the surface and a distinctive distribution through the crown. Untreated Oregon material with strong colour and flash commands a premium.
: Almost certainly not. The solarsteinn mentioned in Icelandic sources as a navigational aid is thought to have been a birefringent or pleochroic crystal, with Iceland spar calcite, cordierite and tourmaline as the leading candidates. The name sunstone for this feldspar is a modern coincidence.
: No, it is twentieth-century. Moonstone has a genuine Indian tradition as chandrakanta; sunstone has almost no ancient tradition at all. The pairing is a neat modern symmetry, which is worth recognising as such while still finding it useful.