Sunstone Identification Guide
How to identify sunstone by its glittering aventurescence (schiller), feldspar cleavage and hardness, and how to separate it from goldstone and aventurine quartz.
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What Sunstone Looks Like
Sunstone is a feldspar (usually oligoclase or labradorite plagioclase, sometimes orthoclase) famous for aventurescence, a glittering, metallic spangled shimmer caused by light reflecting off tiny platy inclusions of hematite, copper, or goethite. Body color ranges from colorless and pale champagne to honey, orange, red, and, in Oregon copper-bearing sunstone, green or bicolor. It is transparent to translucent with a vitreous luster and shows the characteristic flashes of coppery or golden sparkle when tilted under light.
Key Visual Cues
- Metallic glittery spangles (aventurescence/schiller)
- Warm body color: champagne, honey, orange, red, sometimes green
- Transparent to translucent with vitreous luster
- Feldspar cleavage surfaces, sometimes with a sheen
Step-by-Step Field ID Checklist
- Tilt under light. Genuine sunstone shows directional metallic glints from internal platelets, strongest at certain angles.
- Look at the body. A natural warm feldspar body with internal sparkle (not surface glitter) supports sunstone.
- Find cleavage. Feldspar has two cleavage directions meeting near 90 degrees; look for flat reflective planes.
- Test hardness. Sunstone is Mohs 6 to 6.5; it scratches glass faintly and resists a steel knife slightly.
- Check the streak. White streak.
- Assess density. Specific gravity ~2.6 to 2.7, normal feldspar heft.
Diagnostic Tests
- Mohs hardness: 6 to 6.5.
- Streak: white.
- Cleavage: two good directions intersecting near 90 degrees (diagnostic of feldspar).
- Specific gravity: ~2.62 to 2.67.
- Aventurescence: internal metallic platelet reflections, not a painted-on glitter.
- Acid: inert to hydrochloric acid.
Common Look-Alikes and How to Tell Them Apart
- Goldstone (man-made glass): goldstone has an even, dense, uniform copper sparkle and conchoidal glassy fracture with no cleavage; it often contains visible gas bubbles. Sunstone's sparkle is irregular and the stone shows feldspar cleavage.
- Aventurine quartz: aventurine is quartz (Mohs 7), harder, with greenish mica-flake sparkle and no feldspar cleavage; it does not show the warm coppery schiller.
- Peach moonstone: moonstone shows a floating blue or white adularescence (a billowy sheen) rather than discrete metallic glints.
- Citrine/orange quartz: lacks aventurescence entirely and has quartz hardness (7) without cleavage.
- Bronzite/enstatite: these pyroxenes show a bronzy sheen but have distinct cleavage and different crystal habit.
Where Sunstone Is Found
Gem sunstone is found in Oregon, USA (the celebrated copper-bearing labradorite sunstone, the state gem, from basalt flows), as well as India, Norway, Canada, Russia, Tanzania, and Madagascar. Sunstone occurs in igneous rocks such as basalt and granite pegmatites, and in some metamorphic settings. The Oregon material is unusual for being a calcium-rich plagioclase colored by metallic copper inclusions.
Frequently asked questions
How can you tell if it's real sunstone?
Genuine sunstone shows internal metallic aventurescence that flashes at specific tilt angles, has feldspar cleavage in two near-90-degree directions, a hardness of 6 to 6.5, and a white streak. Man-made goldstone instead has uniform glitter, gas bubbles, and no cleavage.
What does sunstone look like?
It looks like a translucent warm-colored feldspar, champagne to honey, orange, red, or green, with a glittering coppery or golden internal sparkle that catches the light when the stone is rotated.
Sunstone vs goldstone, what is the difference?
Goldstone is manufactured glass with uniform, dense copper glitter, gas bubbles, and conchoidal fracture but no cleavage. Natural sunstone is a feldspar mineral with irregular internal schiller and visible cleavage planes.
Is sunstone the same as aventurine?
No. Aventurine is quartz with greenish mica-flake sparkle and Mohs 7 hardness, while sunstone is a feldspar (Mohs 6 to 6.5) with warm coppery aventurescence and feldspar cleavage.
What causes the sparkle in sunstone?
The sparkle, called aventurescence or schiller, comes from light reflecting off tiny platy inclusions of hematite, goethite, or copper aligned within the feldspar crystal.
Sunstone identified by the community
Recent Sunstone specimens identified with Rock Identifier.
