Rock & Mineral Encyclopedia

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

Geode

A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.

A black volcanic glass that reveals concentric rainbow bands of color when cut and polished against the light.

A black volcanic glass threaded with delicate grey, swirling lace-like bands of flow lines that show beautifully when polished.

A translucent apple-green chalcedony colored by nickel, the most prized green variety of the quartz family.

An earthy-toned jasper with vine-like or scenic patterning, valued by lapidaries for warm browns, reds, and creams that polish to a smooth finish.

A common opal with branching, tree-like mineral inclusions that create natural fern, moss, or landscape patterns.

Clear quartz filled with mineral inclusions that look like underwater gardens, mossy landscapes, or floating scenery.

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