Rock Identifier

Rock & Mineral Encyclopedia

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

Smithsonite

Smithsonite

Smithsonite is a zinc carbonate ore famous for glassy botryoidal crusts in blue-green, pink, and yellow hues.

mineral
Millerite

Millerite

A nickel sulfide famous for delicate brass-yellow hairlike crystals that form radiating sprays inside cavities and geodes.

mineral
Flame Agate

Flame Agate

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

gemstone
Pyromorphite

Pyromorphite

A lead phosphate secondary mineral known for barrel-shaped green to yellow crystals formed in oxidized lead deposits.

mineral
Fire Opal

Fire Opal

A translucent to transparent opal in warm yellow, orange, and red tones, prized for body color rather than play-of-color.

gemstone
Wonderstone

Wonderstone

A banded rhyolitic volcanic rock with swirling tan, red, and yellow iron-oxide layers prized as a decorative picture stone.

igneous
Septarian Concretion

Septarian Concretion

A rounded sedimentary nodule cracked internally and filled with veins of yellow calcite, prized for its striking dragon-skin patterning.

sedimentary
Macusanite

Macusanite

A rare translucent yellow-green volcanic glass from the Macusani region of Peru, valued by faceters and sometimes confused with tektites.

igneous
Prehnite

Prehnite

A translucent yellow-green silicate famous for its botryoidal 'grape' clusters, often hosting needle-like sprays of black epidote.

mineral
Palagonite

Palagonite

A yellow-brown alteration material formed when basaltic volcanic glass reacts with water, common in hydrovolcanic tuffs and pillow lavas.

igneous
Cat's Eye Opal

Cat's Eye Opal

An opal cut to show chatoyancy, a sharp moving band of light like a cat's eye, usually in honey, green or yellow common opal.

gemstone
Montana Moss Agate

Montana Moss Agate

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

gemstone
Olive Tourmaline

Olive Tourmaline

An earthy olive to yellowish-green tourmaline, a muted green-brown gem variety colored by iron with subtle warm undertones.

gemstone