Rainbow Obsidian is a naturally occurring volcanic glass characterized by shimmering, multicolored bands caused by nano-inclusions of magnetite. When polished or carved at the correct angle, it displays a distinct iridescent sheen that changes under light. It is primarily sourced from volcanic regions in Mexico and is highly prized by lapidaries for its unique play of color.
Is this rainbow obsidian?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch rainbow obsidian with a known reference. Rainbow Obsidian sits at Mohs 5-5.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Rainbow Obsidian leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Rainbow Obsidian typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, iridescent.
- 5Look at form & habitCrystal system: amorphous. Typical habit: massive.
Often confused with
Rainbow Obsidian vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside rainbow obsidian
Minerals reported to co-occur with rainbow obsidian. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂
- Mohs hardness
- 5-5.5
- Density
- 2.4 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Amorphous
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Rhyolitic Lava
- Typical price
- $5-50 for slabs and polished specimens
Where rockhounds find rainbow obsidian
Classic worldwide localities
- Mexico
- USA
- Iceland
- Armenia
Field-hunting tip
Look in rhyolitic lava country — that is the host setting where rainbow obsidian typically forms. If you start seeing quartz, feldspar, cristobalite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find rainbow obsidian on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
