Rock & Mineral Encyclopedia

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

Zircon

A natural zirconium silicate gem with high brilliance and fire, often confused with the synthetic imitation cubic zirconia.

A trade name for sheen obsidian whose swirling, patchy iridescence resembles galaxies and nebulae against deep black glass.

A striking blue aluminum silicate famous for bladed crystals and anisotropic hardness that differs dramatically along and across the blade.

Black volcanic glass dotted with radiating spherulite bursts that look like exploding fireworks frozen in the stone.

Obsidian containing spherulites — small radiating spheres of feldspar and cristobalite that crystallized within the cooling volcanic glass.

A chalcedony agate filled with radiating needle-like mineral inclusions, prized for its starburst and spray patterns.

A translucent Wyoming chalcedony filled with delicate black manganese dendrites that resemble tiny ferns, moss, or starbursts.