Rock & Mineral Encyclopedia

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

Rhodonite

A rose-pink manganese silicate marbled with black veins, prized as a tough ornamental and occasionally faceted gemstone.

A hydrated silica gemstone famous for its shimmering play-of-color, ranging from white and black opal to fiery orange fire opal.

A glacier-transported banded agate from the Lake Superior region, colored by iron into rich reds and oranges, and Minnesota's state gemstone.

A group of silicate gemstones best known for deep red but spanning nearly every color, including green tsavorite and orange spessartine.