Rock & Mineral Encyclopedia

Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.

Landscape Opal

A common opal containing dendritic or mossy mineral inclusions that form miniature landscape-like scenes inside the stone.

Obsidian colored brown by iron oxide inclusions, frequently banded or swirled with black as in mahogany obsidian.

An unusually pure, transparent-to-translucent obsidian with few inclusions; truly water-clear specimens are rare in nature.

A natural volcanic glass with rich brown and black mahogany-like swirls created by iron oxide inclusions.

Pink tourmaline cut en cabochon to reveal a moving band of light, a phenomenal gem colored by manganese with parallel inclusions.

A black volcanic glass with a soft, velvety internal sheen caused by aligned microscopic inclusions catching the light.

Volcanic glass tinted red by fine iron-oxide inclusions, often blended with black to form mahogany-patterned obsidian.

Obsidian in gray tones, often semi-translucent, colored by light scattering and minor inclusions within the volcanic glass.

Black volcanic glass with a warm bronze or coppery sheen produced by light reflecting off aligned microscopic inclusions.

Fine acicular (needle-like) tourmaline crystals, often black schorl, frequently seen as slender inclusions within clear quartz.