Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Staurolite Schist
A mica schist studded with brown staurolite porphyroblasts, sometimes forming the cross-shaped twins known as fairy stones.
metamorphicPaintbrush Jasper
A scenic jasper whose flowing streaks of warm color resemble strokes left by a loaded paintbrush.
mineralSonoran Sunset Jasper
A vivid copper-bearing Mexican stone of red cuprite and green chrysocolla that evokes a desert sunset.
mineralBird's Eye Jasper
A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.
mineral
Trapiche Emerald
A rare emerald showing a six-spoked star pattern of dark inclusions, named after the spokes of a sugar-mill wheel.
gemstone
Neon Blue Tourmaline
An intensely glowing copper-bearing tourmaline whose electric neon-blue color makes it one of the most valuable gems in the world.
gemstone
Wacke
A poorly sorted, muddy sandstone with abundant clay matrix between its grains, typically dark and deposited by turbidity currents.
sedimentaryPaintbrush Agate
A plume agate whose inclusions form upright, bristly clusters resembling the strokes of a paintbrush.
gemstoneBahia Agate
A banded and plume agate from the Bahia state of Brazil, known for delicate dendritic and feathery inclusions.
gemstone
Moss Opal
A common opal containing moss- or fern-like mineral inclusions that resemble plants suspended in a pale silica body.
gemstone
Cat's Eye Green Tourmaline
Green tourmaline cut as a cabochon to show a sharp moving band of light (chatoyancy) caused by fine parallel inclusions.
gemstone
Silver Sheen Obsidian
Black volcanic glass displaying a silvery shimmer from light reflecting off aligned microscopic gas bubbles trapped in the obsidian.
crystalReptile Jasper
A green-and-black mottled jasper whose scale-like patterning resembles reptile skin, often linked to Kambaba and crocodile jaspers.
mineral
Shungite
A rare black carbon-rich rock from Russia, noted for containing fullerenes and ranging from dull mineralized stone to lustrous noble shungite.
sedimentary
Loess
A loose, wind-blown silt deposit, typically buff-colored and very fertile, that forms thick blankets and stands in steep cliffs.
sedimentary
Snow Quartz
An opaque, snow-white variety of quartz whose milky color comes from countless tiny gas and fluid inclusions.
crystalFlame Obsidian
Black volcanic glass that flashes flame-like bands of iridescent color when light strikes aligned nanoscale inclusions.
igneous
Cat's Eye Tourmaline
Tourmaline displaying chatoyancy, a moving band of light caused by parallel tube-like inclusions, when cut as a cabochon.
gemstone
Tibetan Quartz
Clear quartz mined in the Himalayan region, often double-terminated and containing dark hematite or carbon inclusions.
crystal
Rutile
Rutile is a major titanium ore and the famous golden needle inclusion that gives rutilated quartz its shimmering threads.
mineralCat's Eye Morganite
Pink beryl (morganite) that shows chatoyancy, a moving band of light, when cut as a cabochon, thanks to parallel tube inclusions.
gemstone
Star Aquamarine
A rare blue beryl that shows asterism, a moving star of light from intersecting sets of parallel inclusions, when cut as a cabochon.
gemstone
Brecciated Jasper
A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.
sedimentary
Khondalite
A high-grade metamorphic gneiss of garnet, sillimanite, quartz, and graphite, derived from ancient aluminous sediments.
metamorphic