Velvet Obsidian Identification Guide

What Velvet Obsidian Looks Like

Velvet obsidian is a sheen variety of obsidian (natural volcanic glass) that displays a soft, satiny, velvet-like reflective glow when light strikes it at the right angle. The body is dark - black to brownish-black - and the sheen, caused by aligned microscopic gas bubbles or mineral microlites, appears as a muted silver, gray, bronze, or subtly colored shimmer across the surface (less metallic than gold/silver sheen, more diffuse and "velvety"). Like all obsidian it is glassy, with a brilliant vitreous luster on fresh surfaces and razor-sharp conchoidal fracture.

Step-by-Step Field-ID Checklist

1. Confirm it's obsidian. Glassy luster, conchoidal fracture, sharp edges, no crystal grains.
2. Find the sheen. Tilt the piece under a single light source; a soft, diffuse velvety glow should sweep across the surface.
3. Check the body color. Black to brownish-black.
4. Hardness test. ~5-5.5; steel scratches it, it scratches window glass slightly.
5. Hold a thin edge to light. Obsidian is translucent at thin margins.
6. Look for the cause of sheen - the glow comes from within (aligned microscopic inclusions), not a surface coating.

Key Diagnostic Tests

• Mohs hardness: ~5-5.5.
• Streak: White.
• Fracture: Conchoidal, no cleavage; sharp edges.
• Magnetism: None (rare weak response if magnetite microlites abundant).
• Acid: No reaction (silica glass).
• Density: ~2.35-2.6 g/cm3.

Common Look-Alikes

• Gold/silver sheen obsidian: Same family but with a brighter, more metallic single-color sheen; velvet sheen is softer and more diffuse.
• Rainbow obsidian: Shows multiple iridescent color bands rather than a uniform velvety glow.
• Black tourmaline/schorl: Crystalline with striated prisms and cleavage tendencies, not glassy conchoidal fracture.
• Black onyx/black chalcedony: Harder (Mohs 7), no internal sheen, waxier.
• Hematite/black glass slag: Hematite is much denser with a red streak; manufactured slag glass often shows round bubbles and swirls.

The diagnostic package is glassy conchoidal fracture, white streak, Mohs ~5-5.5, and a soft internal velvety sheen on a black body.

Where It Is Found

Like other sheen obsidians, velvet obsidian comes from silica-rich volcanic flows. Notable obsidian sources include Mexico (a major source of sheen obsidians), the western United States (Oregon, California, Idaho, Arizona), and other young volcanic regions worldwide.