Rock & Mineral Encyclopedia

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

Graphite Schist

A dark, foliated schist rich in graphite that leaves a grey-black mark and forms from metamorphosed carbon-rich sediments.

A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.

Tabular quartz crossed by a milky white thread-like line marking where the crystal repeatedly cracked and re-healed.