Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Palagonite
A yellow-brown alteration material formed when basaltic volcanic glass reacts with water, common in hydrovolcanic tuffs and pillow lavas.
igneous
Clear Obsidian
An unusually pure, transparent-to-translucent obsidian with few inclusions; truly water-clear specimens are rare in nature.
igneous
Pele's Hair
Fine, golden, hair-like strands of basaltic volcanic glass spun from fluid lava droplets during eruptions, named for the Hawaiian volcano goddess.
igneous
Water Opal
A transparent, colorless opal that looks like water or jelly, sometimes flashing subtle play-of-color from within.
gemstoneGolden Peacock Obsidian
A natural sheen obsidian showing a warm gold shimmer plus peacock iridescence, caused by aligned nanoparticle layers within black glass.
igneous
Red Obsidian
Volcanic glass tinted red by fine iron-oxide inclusions, often blended with black to form mahogany-patterned obsidian.
crystal
Fire Obsidian
A rare obsidian showing brilliant fiery iridescence caused by thin nanolayers of magnetite crystals diffracting light within the glass.
crystal
Silver Sheen Obsidian
Black volcanic glass displaying a silvery shimmer from light reflecting off aligned microscopic gas bubbles trapped in the obsidian.
crystalCalico Obsidian
A mottled, multicolored obsidian blending black, brown, grey, and tan patches like a calico cat's patchwork coat.
igneousFireworks Obsidian
Black volcanic glass dotted with radiating spherulite bursts that look like exploding fireworks frozen in the stone.
igneousVelvet Obsidian
A black volcanic glass with a soft, velvety internal sheen caused by aligned microscopic inclusions catching the light.
igneous
Rainbow Obsidian
A black volcanic glass that reveals concentric rainbow bands of color when cut and polished against the light.
igneousCosmic Obsidian
A trade name for sheen obsidian whose swirling, patchy iridescence resembles galaxies and nebulae against deep black glass.
igneousCloudy Obsidian
Obsidian with a hazy, cloud-like translucency caused by uneven distribution of tiny bubbles or incipient crystallites in the glass.
igneousPeanut Obsidian
Black volcanic glass studded with oval, peanut-shaped grey-white spherulites of radiating crystals frozen in the glass.
igneous
Banded Obsidian
Volcanic glass marked by parallel or swirling bands of differing color that record the flow layering of cooling lava.
igneous
Apache Tears
Rounded nodules of translucent obsidian, named after a Native American legend, that glow smoky brown when held to light.
igneousSpiderweb Obsidian
Black volcanic glass crossed by a fine network of grey or brown veins that resemble a spider's web.
igneousStripe Obsidian
Obsidian crossed by parallel flow bands of differing color, formed as layers of lava with slightly different compositions froze into glass.
igneousGold Sheen Obsidian
A black obsidian displaying a golden metallic sheen caused by light reflecting off aligned microscopic gas bubbles or mineral inclusions.
igneous
Pumpkin Obsidian
An orange-to-rust colored variety of natural volcanic glass whose warm tone comes from iron oxide staining within the obsidian.
igneousSmoky Obsidian
Translucent smoky-gray obsidian that transmits a hazy light, intermediate between clear and fully black volcanic glass.
igneous
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