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Sunstone: Which Feldspar Is It, and Is the Color Natural?

By Digital Towns Crystals ยท Last reviewed October 8, 2026

Short answer: sunstone is a name for feldspar that glitters, not a single mineral. The classic material from Norway and India is oligoclase, a sodium-rich plagioclase whose sparkle comes from flat hematite flakes. Oregon sunstone is mostly labradorite, a more calcium-rich plagioclase, colored and spangled by native copper. Orthoclase sunstone also exists. In the 2000s, red "Tibetan" andesine sold as natural sunstone was shown to be pale Inner Mongolian feldspar with copper diffused in, so origin and treatment questions matter.

Why is sunstone more than one mineral?

Because the name describes an effect. GIA's sunstone description says that both the orthoclase and the plagioclase branches of the feldspar family have a sunstone variety, and that the name refers to the gem's appearance rather than to its chemical makeup. The effect is aventurescence: a sparkly, metallic-looking luster caused by flat, reflective inclusions, which sunstone fanciers sometimes call "schiller". When aventurescence is present, gemologists call the material aventurine feldspar.

Historically, oligoclase came first. Geology.com notes that the first materials to be called sunstone because of their aventurescence were specimens of oligoclase, and that labradorite and orthoclase with strong aventurescence were added to the name later.

The three are told apart with instruments, not by eye. GIA's fact sheet gives the numbers:

Feldspar Formula Refractive index Specific gravity Typical source
Orthoclase sunstone KAlSi3O8 1.518 to 1.526 2.58 Rare
Oligoclase sunstone Plagioclase, Na-rich 1.537 to 1.547 2.65 Norway, India, Tanzania
Labradorite sunstone Plagioclase, more Ca 1.559 to 1.568 2.70 Oregon

GIA lists a Mohs hardness of 6.0 to 7.2 across sunstone types (GIA sunstone overview). Oligoclase and labradorite are both members of the plagioclase series, a solid solution between sodium-rich NaAlSi3O8 and calcium-rich CaAl2Si2O8. The farther toward calcium, the higher the refractive index and density, which is how a gem lab places a stone.

What makes Oregon sunstone different?

Oregon material is a different feldspar with a different inclusion. Geology.com's labradorite article states that much of the gem-quality feldspar mined in Oregon and sold as "Oregon Sunstone" is actually labradorite feldspar. Its plagioclase page adds that in Oregon, transparent gem-quality labradorite in yellow, orange, red, blue or green is also called sunstone when it is mined from the same deposit as the aventurescent material, even if it does not glitter.

The glitter itself comes from copper. GIA describes Oregon sunstone as a transparent feldspar with glittery copper inclusions, and its quality-factor page says all Oregon sunstones have an extra sheen caused by copper, even when the copper platelets are too small to produce actual aventurescence (GIA sunstone quality factors). That copper also produces the reds and greens, and some stones are bicolored or even show color change. Deep red stones from the Ponderosa mine are marketed as "spinel red".

Geology and history

The Oregon stones occur in certain basalt flows in Lake County and Harney County, where Geology.com says the sunstone occurs as phenocrysts within the basalt: crystals that grew in the magma before it erupted. Some is dug from the weathered zone above the flows. GIA's history page records early twentieth century reports of sunstone in ancient lava fields of the Warner Valley, and notes that Native Americans there may have been the first collectors. Geology.com adds that Tiffany and Company once held claims near Plush, calling the clear stones "Plush Diamonds", and that after commercial deposits were found in the early 1980s, the Oregon legislature named Oregon Sunstone the official state gemstone in 1987.

The Bureau of Land Management reserves one area in Lake County as a public collecting area where anyone can look for sunstone and keep what they find for personal use, but not for trade or commercial purposes. Fee-dig mines near Plush offer the same experience on private claims.

How does oligoclase sunstone compare?

Classic oligoclase sunstone looks different in the hand: usually translucent rather than water-clear, orange to red-brown, with a dense, coppery-gold glitter that comes from hematite rather than copper. Geology.com notes that sunstone from India is thought to have hematite inclusions rather than the copper of Oregon material, and that a 10x loupe or gem microscope can show they are not copper. Minerals.net lists hematite, sometimes goethite or pyrite, as the glitter-forming inclusions, and describes rare star sunstone with four-rayed asterism.

Norway was the old classic source. Geology.com illustrates oligoclase sunstone from Kragero, and records that deposits near Lake Baikal in Russia were mined in the early 1800s and southern Norway in the late 1800s. Today most low-cost tumbled and bead sunstone comes from India. Tanzanian material can carry hematite flakes over a millimeter across, which gives a coarse, mirror-like flash.

What was the andesine scandal?

In the early 2000s, a red to green feldspar appeared in quantity, sold as natural "Tibetan sunstone" or "Tibetan andesine" (andesine is the plagioclase between oligoclase and labradorite). Its colors rivaled Oregon's top stones at a fraction of the price, and it was marketed as untreated.

Laboratories did not accept the story. George Rossman's chronology in Gems & Gemology explains that red copper-bearing plagioclase from Oregon had been on the market for over a century, and that new localities were then reported in the Democratic Republic of the Congo and in Tibet or an unspecified part of China. Extensive studies of composition, spectroscopy, appearance and isotopes suggested that much of the red andesine on the market was the product of laboratory diffusion of copper into pale yellow andesine from Inner Mongolia (GIA, The Chinese Red Feldspar Controversy). Traces of copper-containing fluxes on rough stones, and especially argon isotope measurements, showed the material had recently been heated to high temperatures under conditions where copper could diffuse in. GIA's sunstone description summarizes the outcome: the stones had been represented as untreated plagioclase sunstone from Tibet, but the evidence pointed to pale andesine from Mongolia infused with copper.

The rule that came out of it is simple. A red or green plagioclase sold as "andesine", "Tibetan sunstone" or "Congo sunstone" should be assumed copper-diffused unless a lab report says otherwise. Natural Oregon material is the reference that the treated stones were trying to imitate.

How do you tell sunstone from goldstone and aventurine?

Goldstone is glass. Geology.com's goldstone article explains that reddish brown goldstone is made by dissolving copper oxide in molten glass and cooling it very slowly, so that tiny octahedral copper crystals grow inside; under magnification they show triangular faces. Sunstone's flakes are flat platelets aligned in one plane, so the glitter switches on and off together as the stone is tilted, while goldstone's crystals sparkle evenly from every angle. Goldstone also shows round gas bubbles. Orange aventurine is quartz, not feldspar; see the aventurine guide for that separation. Sunstone versus moonstone, its cool-toned feldspar cousin, is covered on the moonstone page.

How should you care for sunstone?

GIA's care page gives the key facts: feldspars combine moderate hardness with cleavage in two directions, which gives sunstone a Poor toughness rating, so pendants and earrings are safer than rings (GIA sunstone care). Its color is stable to light. Avoid heat, ultrasonic and steam cleaners, and bleach, since feldspars are rapidly attacked by hydrochloric acid. Warm soapy water is the safe method, and the only one for the rare fracture-filled stone.

What is sunstone associated with in crystal traditions?

In crystal traditions, sunstone is associated with warmth, optimism and the sacral chakra, by way of its orange color. GIA's history page also records an Oregon Native American legend in which a wounded warrior's blood colored the stones red. These are stories and associations, not properties.

What to look for when you buy sunstone

Decide first which sunstone you want. Inexpensive tumbled and rough sunstone is almost always Indian oligoclase with hematite glitter, and it is honestly priced at a few dollars. Geology.com notes that small cabochons with a pleasant orange color and nice aventurescence can be bought for under $50, while bright red and bicolor stones that have been nicely faceted can sell for over $1000 per carat. Anything vivid red, transparent and cheap is the profile of diffused andesine.

Checks: tilt the piece under a single light and watch the glitter flash in one plane; look with a loupe for flat platelets rather than triangles or bubbles; ask for locality; and for any red faceted stone, ask whether it is Oregon material or andesine.

  • Sunstone: natural pieces at an entry price, the right way to see hematite aventurescence flash as the stone is turned.
  • Sunstone tumbles: polished tumbled sunstone; look for the orange body color and glitter concentrated in one direction.
  • Labradorite flashy palm stone: the same plagioclase species as Oregon sunstone, but showing labradorescence, a broad color flash, instead of glitter.
  • Peach moonstone: a feldspar cousin with a soft floating glow rather than metallic sparkle, useful for comparing the two optical effects.

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Frequently asked questions

What mineral is sunstone?

Sunstone is feldspar that shows aventurescence, a glitter from flat reflective inclusions. Most sunstone is plagioclase: oligoclase from Norway, India and Tanzania, or labradorite from Oregon. A rarer orthoclase sunstone also exists. The name describes the look, not one chemical formula.

Is Oregon sunstone really labradorite?

Mostly, yes. Much of the gem feldspar mined in Oregon and sold as Oregon sunstone is labradorite, a calcium-richer plagioclase. Its glitter and color come from copper rather than the hematite seen in Indian and Norwegian oligoclase sunstone.

What is andesine and why is it controversial?

Andesine is a plagioclase feldspar. In the 2000s, red and green andesine sold as untreated Tibetan sunstone was shown by GIA and other labs, using argon isotopes and flux traces, to be largely pale Inner Mongolian andesine with copper diffused in at high temperature.

Is goldstone the same as sunstone?

No. Goldstone is man-made glass in which copper crystals grow as the melt cools slowly. Sunstone is natural feldspar with flat hematite or copper platelets. Under a loupe, goldstone shows triangular copper crystals and bubbles, and it sparkles from every angle.

Does sunstone fade in the sun?

No. GIA states that sunstone's color is stable to light. Heat, bleach, ultrasonic and steam cleaners are the risks. Clean it with warm soapy water and protect it from knocks, because two directions of cleavage make it prone to chipping.

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