Rock & Mineral Encyclopedia

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

Ruby

The red, chromium-colored variety of corundum, prized as one of the most valuable colored gemstones and second only to diamond in hardness.

A striking rock of green zoisite studded with red-pink ruby crystals and black hornblende, also called anyolite.

A chromium-rich pyrope garnet whose intense blood-red color comes from chromium, often mined from ant hills and kimberlite weathering.

Natural emerald crystals still embedded in their host rock, prized as mineral specimens that show how the gem grew in place.

The red to raspberry-pink variety of tourmaline, prized for its vivid ruby-like color that holds under both daylight and artificial light.

Small, intensely red chrome-pyrope garnets from the Czech Bohemian region, famous for densely set antique Victorian jewelry.

Small, bright chrome-pyrope garnets famously brought to the surface by harvester ants on the Navajo lands of Arizona.