Rock & Mineral Encyclopedia

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

Blood Agate

A deep red banded agate colored by iron oxides, valued as a vivid red lapidary and jewelry stone.

Australia's classic light-bodied precious opal from Coober Pedy, famed for milky white stones flashing pastel rainbow play-of-color.

A chalcedony agate with red, orange, and yellow plume or banding patterns that rise like dancing flames within the stone.

A jasper marked with soft feather- or plume-like mineral inclusions that drift through a pale silica body.

Ancient wood whose organic tissue has been replaced by silica, preserving the grain, rings, and structure of the original tree in stone.