Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Chalcedony
A waxy, translucent microcrystalline form of quartz that serves as the parent group for agate, jasper, carnelian, and onyx.
mineral
Pyrargyrite
A silver antimony sulfosalt known as dark ruby silver, an important silver ore with deep red internal reflections.
mineral
Pyrope Garnet
The magnesium-rich garnet famed for its intense blood-red 'fire,' historically the Bohemian garnet of Victorian jewelry.
gemstone
Chrome Pyrope
A chromium-rich pyrope garnet whose intense blood-red color comes from chromium, often mined from ant hills and kimberlite weathering.
gemstone
Cuprite
Cuprite is a deep red copper oxide and an important secondary copper ore, prized for its rare ruby-red gem crystals.
mineralFeather Jasper
A jasper marked with soft feather- or plume-like mineral inclusions that drift through a pale silica body.
mineralKiwi Jasper
A speckled green-and-black stone resembling kiwi fruit, technically a quartz-amazonite aggregate rather than true jasper.
mineral
Rubellite
The red to raspberry-pink variety of tourmaline, prized for its vivid ruby-like color that holds under both daylight and artificial light.
gemstonePink Obsidian
A pink to rose volcanic glass; some is natural iron-tinted obsidian while much sold commercially is color-treated glass.
igneous
Gem Silica
A rare, intensely blue chalcedony colored by copper-rich chrysocolla, prized as the most valuable of the blue chalcedonies.
gemstone
Geode
A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.
mineral
Deschutes Jasper
A prized Oregon picture jasper from the Deschutes region known for soft scenic landscapes in cream, tan, and blue-gray.
mineral
Red Garnet
The classic deep-red garnet — usually almandine or pyrope — long worn as the fiery 'carbuncle' gem and January's birthstone.
gemstoneSyrian Garnet
Syrian Garnet is an old trade name for fine deep-red almandine, historically tied to the Syriam region and prized as 'precious garnet.'
gemstoneBlue Obsidian
Blue-colored volcanic glass; genuine natural blue obsidian is very rare, while much blue obsidian on the market is manufactured glass.
crystal
Sphalerite
Zinc sulfide and the chief ore of zinc, prized when transparent for its extreme fire that exceeds diamond.
mineral
Yellow Obsidian
Yellow to golden volcanic glass; natural examples owe their color to iron, though much bright yellow obsidian on the market is manufactured glass.
igneousSnakeskin Jasper
An opaque patterned jasper named for its scaly, snakeskin-like surface markings of interlocking tan and brown cells.
mineralFlame Jasper
A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.
mineral
Red Opal
An opal with a deep red body color, often a variety of Mexican fire opal, prized for its warm, glowing intensity.
gemstone
Howlite
A white, porous borate mineral webbed with gray-black veins, widely dyed to imitate turquoise and other stones.
mineral
Zebra Jasper
A black-and-white striped chalcedony-quartz rock whose bold zebra-like banding makes it a popular ornamental and lapidary stone.
sedimentary
Red Tourmaline
Vivid red to raspberry tourmaline, the most intense colors are marketed as rubellite, colored by manganese in the elbaite structure.
gemstone
Spinel
A durable magnesium aluminum oxide gem that occurs in many colors and was long mistaken for ruby.
gemstone