Rock & Mineral Encyclopedia

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

Blue Goldstone

A man-made glittering glass colored deep blue with cobalt and studded with tiny copper crystals that mimic a starry night sky.

A bronze-colored iron sulfide notable for being the most magnetic of the common sulfide minerals and an important nickel host.

The serene blue-to-sea-green variety of beryl, aquamarine is a durable gemstone colored by trace iron and birthstone for March.

A brilliant green grossular garnet colored by chromium and vanadium, rivaling emerald with superior brilliance and durability.

The pink to peach variety of beryl, better known as morganite, colored by manganese and prized for its gentle pastel hues.

An intensely green tourmaline colored by chromium and vanadium, prized for its vivid emerald-like color from East Africa.

Tourmaline in blue tones, encompassing iron-colored indicolite and the rare neon copper-bearing Paraiba, among the scarcer tourmaline colors.

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

The golden-yellow gem variety of beryl, colored by iron, prized for its bright sunshine hue and excellent durability.

Obsidian in gray tones, often semi-translucent, colored by light scattering and minor inclusions within the volcanic glass.

A bright, fresh lime to yellowish-green elbaite tourmaline (verdelite), colored by iron and trace manganese for a lively spring-green tone.

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

A deep, rich forest-green elbaite tourmaline (verdelite) colored mainly by iron, with strong pleochroism and excellent durability.