Rainbow Velvet Obsidian Identification Guide

What Rainbow Velvet Obsidian Looks Like

Rainbow velvet obsidian is a variety of sheen obsidian (natural volcanic glass) prized for a soft, muted, velvety multicolored iridescence rather than the sharp bright bands of ordinary rainbow obsidian. The base is black; aligned magnetite nanoparticle layers diffract light into gentle gold, green, violet, and pink hues.

• Color: black base with a satiny, velvety rainbow sheen
• Luster: vitreous, but the sheen reads as soft/satiny
• Transparency: opaque; thin edges translucent brown
• Habit: massive glass, no crystal form

Step-by-Step Field ID Checklist

1. Turn the polished piece slowly under a single light. A diffuse, low-contrast "velvet" band of color should glide across the surface.
2. Confirm it is glass by checking a chip for conchoidal fracture.
3. Backlight a thin edge to see the brown translucency typical of obsidian.
4. Test hardness with a steel knife.
5. Heft it — low density confirms glass over denser gem material.

Key Diagnostic Tests

• Mohs hardness: 5–5.5; quartz scratches it, it scratches against a knife edge only marginally.
• Fracture: conchoidal, no cleavage — confirms volcanic glass.
• Streak: white to gray.
• Specific gravity: ~2.35–2.6.
• Magnetism: not attracted to a hand magnet despite microscopic magnetite.
• Acid: no reaction.

Common Look-Alikes and How to Tell Them Apart

• Rainbow obsidian (standard): shows brighter, sharper concentric color rings; velvet variety is softer and more diffuse. Both are the same glass.
• Gold/silver sheen obsidian: single-color metallic sheen versus multicolor.
• Black labradorite/spectrolite: a feldspar with cleavage and hardness 6–6.5, sharper metallic flashes, not glassy conchoidal fracture.
• Iridescent man-made glass: check for mold seams, perfectly even sheen, and rounded gas bubbles.

Where It Is Found

Like other sheen obsidians, it is sourced from Mexico and the western United States, where rapid cooling of silica-rich lava trapped oriented magnetite microlites.

Collector's Notes and Common Mistakes

"Velvet" is a grading and marketing distinction rather than a separate mineral — it describes sheen obsidian whose magnetite layering produces a soft, low-contrast, satiny iridescence instead of bright bands. Because the effect is orientation-dependent, the same nodule can yield velvety, brilliant, or dead-black slabs depending on the cut, so test multiple angles before finishing a piece. The main authenticity risk is iridescent manufactured glass: look for mold seams, perfectly even sheen visible from every direction, and round trapped bubbles. Confirm the material is true obsidian with the basics — glassy conchoidal fracture, hardness 5–5.5, brown translucency on thin edges, and no magnet response despite the magnetite. Keep finished cabs and spheres away from harder stones, since obsidian scratches easily, and avoid thermal shock, which can crack glass. When grading, the most prized velvet pieces show an even, full-spectrum sheen with no distracting bubbles or fractures.