Rock & Mineral Encyclopedia

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

Granodiorite

A common coarse-grained intrusive rock like granite but richer in plagioclase than potassium feldspar.

A chalcedony agate with red, orange, and yellow plume or banding patterns that rise like dancing flames within the stone.

A warmly colored chalcedony agate with reds, oranges, golds, and pinks that blend like the glowing bands of a sunset sky.

A translucent chalcedony from Montana filled with black and red dendritic inclusions that look like moss, ferns, or scenic landscapes.

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

A dark, foliated schist rich in needle-like hornblende crystals, formed by metamorphism of mafic igneous rocks.

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

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

A lustrous black titanium-rich garnet of the andradite series, found in alkaline igneous rocks like nepheline syenite and ijolite.

An earthy aluminum-rich residual rock and the world's principal ore of aluminum, often showing distinctive pea-like pisolites.

A rare mushroom-shaped tourmaline growth habit, typically magnesium-rich dravite/uvite, prized by collectors for its fungus-like cap-and-stem form.

Tabular quartz crossed by a milky white thread-like line marking where the crystal repeatedly cracked and re-healed.