Oregon Sunstone: the copper feldspar, nature and care

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Oregon sunstone is a labradorite-type feldspar filled with tiny copper particles. Red, green or bicoloured: Oregon's state gem since 1987. Treatments and choosing.

Key points

Colour	colourless, pale yellow, orange, pink, red, green; bicoloured; rarely blue
Mineral family	plagioclase feldspar of the labradorite type, rich in calcium (about 70% anorthite for the Ponderosa mine)
Cause of the effect	tiny particles of native copper ('schiller'), which give glitter and colours
Hardness (Mohs)	about 6 to 6.5
Density	about 2.7 (indicative value for plagioclases of this type)
Deposits	Oregon (Lake and Harney counties); Dust Devil, Sunstone Butte and Ponderosa mines
Status	Oregon's state gemstone since 1987
Treatments and imitations	feldspars coloured by copper diffusion, sold in the early 2000s as 'andesine'; aventurine glass (goldstone)

What is Oregon sunstone?

Oregon sunstone is a plagioclase feldspar: a mineral related to labradorite, rich in calcium. The GIA describes it as a natural labradorite containing copper, with a composition of about 70% anorthite for the Ponderosa mine, on the border between labradorite and bytownite. It is transparent to translucent and can be colourless, pale yellow, pink, orange, red or green; some stones are bicoloured, red and green, which makes them a rarity. Its hardness is about 6 to 6.5.

It has been the state gemstone of Oregon since 1987. It is not the same object as the classic 'sunstone', an oligoclase feldspar with a glittering sheen (Norway, India): see the page sunstone.

Where do the colours and the glitter come from?

What sets Oregon sunstone apart is copper. The GIA describes tiny platelets of native copper, the 'schiller', which reflect light and give a golden glitter (like aventurine or classic sunstone). The more copper the stone contains, the more marked the effect and colour. A GIA study (2023) explains that the reds and greens come from the absorption and scattering of light by nanometre-sized copper particles. In some stones, the colour shifts from red to green depending on the viewing direction (pleochroism).

The pieces come from a few sites in Lake and Harney counties: the Ponderosa mine, near Burns, known for its reds and pinks; the Dust Devil mine in the Rabbit Basin, which produces a wide variety of colours; and Sunstone Butte, a cinder cone known for large crystals and bluish greens.

The scandal of copper-treated feldspars

In the early 2000s, cheap red and green feldspars, sold as 'andesine' from the Congo or Tibet, flooded the market. It was later shown that copper had been artificially diffused into pale feldspars to colour them. A natural red andesine, untreated, was later authenticated from Tibet. These events damaged buyers' confidence in copper feldspars.

For you: an authentic Oregon sunstone comes from Oregon and is sold with that origin, which is a clearer guarantee than 'andesine' alone. Colourless or pale yellow rough material is 'easy to treat', according to the gemmological literature. A laboratory can distinguish natural stones from treated ones. See how to read a label.

Traditional symbolism

The name evokes the sun, warmth, joy and vitality. In the world of crystals, sunstone is linked to optimism and creative drive.

These associations are symbolic and modern; no study shows any effect on mood or health.

Traditional correspondences

Area	Correspondence cited
Chakra	solar plexus, or sacral
Element	fire
Signs	Leo, Aries, Sagittarius (very variable)
Keywords	warmth, joy, vitality

See the solar plexus chakra and the origin of the chakras.

How to use it

As jewellery: faceted stone or cabochon, as a pendant or in a ring worn with care; the hardness of 6 to 6.5 means the stone must be protected from knocks (jewellery guide).
As a collector's piece: a faceted gem is a collector's object.
For meditation: turning the stone to bring out the glitter is an exercise in attention (tutorial).

Care and cleansing

Cleaning: lukewarm water, mild soap, soft brush, then a cloth.
Ultrasonic cleaners and steam: to be avoided, as feldspars have cleavage and the stones may have fractures.
Knocks: feldspars split along two cleavage planes: store them separately.
Sunlight: a brief exposure is harmless; for treated stones, avoid strong heat.
Acids, salt: to be avoided.
Symbolic cleansing: smoke, sound or moonlight (guide).

Recognising a real Oregon sunstone

Sign	Natural Oregon sunstone	To question
Origin	Oregon stated (mine, county)	'andesine' or 'sunstone' with no origin
Colours	uneven zones, bicoloured stones, red-green pleochroism	very bright, uniform red or green on a pale stone
Glitter	irregular copper flecks, sometimes absent	regular flecks like confetti (aventurine glass)
Fracture	flat cleavage	rounded fracture, bubbles (glass)

Aventurine glass (goldstone) imitates the glitter; its glitter is very regular and it has no cleavage. Only a gemmological laboratory can reliably tell a natural feldspar from a treated one. See real or fake stone and our commitments.

How to choose

Fine red and green gems are rare and expensive: the GIA cites more than US$1,000 per carat for fine specimens over five carats. Pale yellow and colourless stones, or small pieces, are more affordable. Ask for the origin (the name of the mine if possible) and a certificate for a valuable stone. For a glittering cabochon, the choice is wider, but the seller's honesty remains the key.

Pairings: with sunstone, moonstone or labradorite, the other optical feldspars.

Frequently asked questions

Is Oregon sunstone a real stone?

Yes, it is a natural feldspar of the labradorite type, coloured and glittering from tiny copper particles. It has been Oregon's state gemstone since 1987.

What is the difference from sunstone?

Classic sunstone is an oligoclase feldspar with golden flecks. Oregon sunstone contains native copper and can be red or green.

Are red and green sunstones treated?

Oregon ones are natural. However, feldspars coloured by copper diffusion were sold under the name andesine in the early 2000s.

What is the hardness of Oregon sunstone?

About 6 to 6.5 on the Mohs scale, with cleavage: avoid knocks.

Where is Oregon sunstone found?

In Lake and Harney counties (Dust Devil, Sunstone Butte and Ponderosa mines).