Mint Obsidian Identification Guide
How to identify Mint Obsidian, a pale green-tinted volcanic glass, by its glassy luster, conchoidal fracture, and low density.
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What Mint Obsidian Looks Like
Mint Obsidian is a green-tinted volcanic glass with a soft minty or pale green coloration. Most natural green tints in obsidian are subtle; strongly even, bright mint-green "obsidian" is frequently man-made glass, so testing matters.
- Color: Pale to medium green, sometimes mottled or banded with gray/black.
- Luster: Bright vitreous (glassy).
- Transparency: Translucent to opaque depending on thickness.
- Habit/form: Massive, amorphous; no crystals or cleavage.
Step-by-Step Field ID Checklist
- Confirm it is glass: Vitreous luster, smooth conchoidal fracture, razor edges.
- Backlight it: Natural obsidian glows translucent with often slightly uneven, swirly coloration; perfectly uniform clarity and color hints at manufactured glass.
- Look for flow features: Faint banding or wisps suggest natural volcanic flow.
- Check for round bubbles / mold seams: These indicate man-made glass, not obsidian.
- Run the hardness and density tests below.
Key Diagnostic Tests
- Mohs hardness: ~5–5.5.
- Streak: White to pale.
- Fracture: Conchoidal; no cleavage.
- Density: ~2.35–2.6 g/cm3 — light.
- Acid: No reaction to dilute HCl.
- Magnetism: None.
Common Look-Alikes and How to Tell Them Apart
- Manufactured green glass (slag/art glass): The most common "mint obsidian" on the market — look for mold seams, perfectly spherical bubbles, and unnaturally uniform color. Natural obsidian shows flow swirls and irregular inclusions.
- Green chalcedony/chrysoprase: Harder (7), waxy not glassy, and microcrystalline.
- Moldavite: Also natural glass but a tektite — olive-green, etched/wrinkled natural surface, lighter density (~2.3), and from impact origin, not volcanic.
- Green fluorite: Has cubic cleavage and is softer (4); obsidian has no cleavage.
- Bottle/glass fragments: Frosted or worn, with mold features.
Where It Is Found
Natural green-tinted obsidian comes from rhyolitic volcanic regions (western U.S., Mexico, Iceland). Be aware that much bright "mint obsidian" sold commercially is colored manufactured glass rather than a natural volcanic product.
Frequently asked questions
Is Mint Obsidian real or man-made?
Some green-tinted obsidian is natural, but much bright, evenly colored 'mint obsidian' is manufactured glass. Check for natural flow swirls and irregular inclusions versus mold seams and perfectly round bubbles, which indicate man-made glass.
How can you tell if Mint Obsidian is real?
Confirm it is glass (vitreous luster, conchoidal fracture, hardness ~5–5.5, light weight) and look for natural flow banding rather than mold marks or uniform spherical bubbles.
Mint Obsidian vs moldavite — how to tell them apart?
Moldavite is a natural impact glass (tektite) with a wrinkled, etched olive-green surface and a known impact origin, while mint obsidian is volcanic (or man-made) glass with smooth conchoidal fracture and flow features.
What does Mint Obsidian look like?
It looks like a glossy, pale-to-medium green glass, translucent when backlit, sometimes swirled with gray or black.