Rock & Mineral Encyclopedia

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

Gondite

A metamorphic rock made chiefly of manganese-rich spessartine garnet and quartz, formed from ancient manganese-bearing sediments.

A metamorphosed banded iron formation of alternating quartz and iron-oxide layers, mined as a major iron ore.

A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.

An opaque brown chalcedony whose iron-stained banding mimics deserts, dunes, and distant mountain skylines.

Quartz colored or coated by golden iron oxides such as limonite or goethite, giving a warm sunlit yellow glow.

Clear or milky quartz threaded with black needles of tourmaline (schorl), combining quartz clarity with dramatic dark inclusions.

Ancient chemically deposited rock of alternating iron-oxide and silica bands recording Earth's early oxygenation and a major iron ore source.

A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.

A coarse-grained intrusive igneous rock dominated by alkali feldspar with little or no quartz.

A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.

An orange-to-rust colored variety of natural volcanic glass whose warm tone comes from iron oxide staining within the obsidian.

A dark green jasper-chalcedony speckled with red iron-oxide spots, classically known as bloodstone or heliotrope.

An Australian green rhyolite with eye-like orbs and earthy patterns marketed as jasper, evoking dense rainforest foliage.

A pink-to-red quartz colored by iron oxide inclusions that create a speckled, strawberry-like appearance within clear crystal.

A general term for light-colored, fine-grained volcanic rocks rich in quartz and feldspar, like rhyolite.