Rock & Mineral Encyclopedia

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

Green Aventurine

A green quartz speckled with shimmering fuchsite mica that produces a glittering aventurescence, popular as an affordable ornamental stone.

A metamorphosed banded iron formation of alternating quartz and iron-oxide layers, mined as a major iron ore.

A coarse-grained, speckled intrusive rock built from quartz, feldspar, and mica, forming the bedrock of the continents.

A pegmatitic granite in which quartz and feldspar intergrow to resemble ancient runic or Hebrew script.