Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Gray Obsidian
Obsidian in gray tones, often semi-translucent, colored by light scattering and minor inclusions within the volcanic glass.
igneous
Devitrified Obsidian
Obsidian that has partly crystallized over time, growing pale spherulite clusters within the black glass, as in snowflake obsidian.
igneous
Mahogany Obsidian
A natural volcanic glass with rich brown and black mahogany-like swirls created by iron oxide inclusions.
igneous
Blue Goldstone
A man-made glittering glass colored deep blue with cobalt and studded with tiny copper crystals that mimic a starry night sky.
gemstoneElectric Blue Obsidian
Obsidian with a vivid blue sheen or hue; natural blue obsidian is rare, and intensely uniform blue material is usually manufactured glass.
igneousCat's Eye Obsidian
Sheen obsidian cut so that aligned microscopic inclusions produce a single moving band of light, a cat's-eye effect.
igneousAurora Obsidian
A trade name for rainbow-sheen obsidian whose aligned nanoparticles produce shifting aurora-like bands of color.
igneous
Brown Obsidian
Obsidian colored brown by iron oxide inclusions, frequently banded or swirled with black as in mahogany obsidian.
igneous
Porphyritic Obsidian
Natural volcanic glass speckled with embedded mineral crystals (phenocrysts) such as feldspar or cristobalite that grew before the lava chilled.
igneousMidnight Lace Obsidian
A black volcanic glass threaded with delicate grey, swirling lace-like bands of flow lines that show beautifully when polished.
igneous
White Obsidian
A pale, partly crystallized volcanic glass; genuinely white obsidian is uncommon and usually reflects devitrification or spherulitic growth in the glass.
igneousMidnight Obsidian
A trade name for deep, solid black obsidian, natural volcanic glass prized for its uniform jet-black color and glassy luster.
igneousPink Lady Obsidian
Obsidian showing a pink-to-rose sheen or hue; natural examples get color from interference effects, while uniform pink material is often manufactured glass.
igneousDouble Flow Obsidian
Obsidian formed from two merged lava flows, producing a stone with two distinct bands of sheen or color.
igneous
Snowflake Obsidian
A black volcanic glass speckled with gray-white cristobalite snowflakes, formed as obsidian begins to crystallize.
igneousBronze Sheen Obsidian
Black volcanic glass with a warm bronze or coppery sheen produced by light reflecting off aligned microscopic inclusions.
igneous
Rainbow Velvet Obsidian
A natural sheen obsidian whose black glass displays a soft, velvety rainbow shimmer from aligned magnetite nanoparticles when polished and tilted.
igneousSilver Peacock Obsidian
A natural sheen obsidian combining a bright silver shimmer with iridescent peacock colors, all produced by nanoparticle layers in black glass.
igneous
Pumice
A frothy, lightweight volcanic glass so full of gas bubbles that it can float on water.
igneous
Aragonite
A calcium carbonate mineral and polymorph of calcite, aragonite forms distinctive needle clusters, sea shells, and pearls.
mineral
Spherulitic Obsidian
Obsidian containing spherulites — small radiating spheres of feldspar and cristobalite that crystallized within the cooling volcanic glass.
igneous
Golden Rainbow Obsidian
Black obsidian that displays a golden-to-rainbow iridescent sheen caused by aligned microscopic inclusions reflecting light.
igneous
Moldavite
A rare forest-green natural glass formed by a meteorite impact about 15 million years ago, found mainly in the Czech Republic.
gemstone
Purple Obsidian
Purple-colored volcanic glass; genuine natural purple obsidian is rare, with much purple obsidian being manufactured colored glass.
crystal