Watermelon Obsidian Identification Guide
A field guide to Watermelon Obsidian, a dyed or man-made glass, and how to recognize that this pink-and-green material is treated.
Read the full Watermelon Obsidian encyclopedia entry →
What Watermelon Obsidian Looks Like
"Watermelon Obsidian" is sold as obsidian with pink/red and green zones resembling watermelon. Importantly, natural obsidian does not occur in vivid pink-and-green watermelon patterns; most material on the market is dyed or color-treated glass/obsidian (and some is simply manufactured art glass). Identify it accordingly.
- Color: bright pink to magenta cores with green rinds, or banded pink/green; colors are unusually saturated and even.
- Luster: bright vitreous (glassy).
- Transparency: translucent to opaque.
- Form: massive glass; conchoidal fracture with sharp edges.
Step-by-Step Field Checklist
- Question the color first. Vivid, evenly distributed pink and green is a strong sign of dyeing or man-made glass, not natural obsidian.
- Look for gas bubbles. Round bubbles under a loupe point to manufactured glass.
- Check fracture. Conchoidal (shell-like) curved breaks confirm a glassy material (natural or man-made).
- Examine dye in cracks. Concentrated color in surface fractures indicates dyeing.
- Test hardness. Glass/obsidian ~5-6; brittle, scratches with a hard steel point.
Key Diagnostic Tests
- Mohs hardness: ~5-6.
- Streak: white.
- Cleavage/Fracture: none; conchoidal.
- Density: ~2.4-2.6 g/cm3 for natural obsidian; manufactured glass varies.
- Bubbles & seams: abundant spherical bubbles and any mold seams indicate man-made glass.
- Acid/Magnetism: none.
Common Look-Alikes
- Manufactured/slag glass: the likeliest identity, with uniform color, many bubbles, sometimes seams.
- Watermelon tourmaline: completely different, a crystalline gemstone with pink core/green rind, trigonal crystals, much harder (7-7.5). Do not confuse the names.
- Dyed agate/chalcedony: harder (7), waxy luster, and shows banding rather than glassy conchoidal fracture.
- Natural rainbow/mahogany obsidian: genuine obsidian colors are blacks, browns and sheens, not bright watermelon pink-green.
Where It Is Found
Because true watermelon-colored obsidian is essentially a trade/treated product, there is no natural source; the glass is produced and colored commercially. Genuine obsidian itself forms at silica-rich volcanoes worldwide, but not in this color scheme.
Frequently asked questions
Is Watermelon Obsidian natural?
No. Natural obsidian does not occur in bright pink-and-green watermelon colors; the material sold under this name is dyed or man-made glass.
How can you tell Watermelon Obsidian is treated?
Look for unnaturally vivid, even pink and green coloration, abundant round gas bubbles, possible mold seams, and dye concentrated in surface cracks.
Is Watermelon Obsidian the same as watermelon tourmaline?
No. Watermelon tourmaline is a natural crystalline gemstone (hardness 7-7.5) with a pink core and green rind, while watermelon obsidian is colored glass.
What is Watermelon Obsidian actually made of?
It is volcanic or manufactured glass that has been dyed or colored; despite the name it is not a naturally pink-and-green volcanic glass.