Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Crystal Opal
Precious opal with a transparent or translucent body, letting play-of-color glow with exceptional depth and clarity.
gemstoneSesame Jasper
A finely speckled pale jasper trade stone named for its sesame-seed-like flecks, closely related to Kiwi Jasper.
mineral
Kyanite Schist
A mica schist containing bladed blue kyanite crystals, a marker of medium- to high-grade metamorphism of aluminous rocks.
metamorphicWoodbine Jasper
An earthy-toned jasper with vine-like or scenic patterning, valued by lapidaries for warm browns, reds, and creams that polish to a smooth finish.
gemstoneImperial Jasper
A prized Mexican jasper known for pastel green, lavender, and cream orbicular patterns that take an exceptional polish.
mineral
Marble
A metamorphosed limestone of interlocking calcite crystals, prized for sculpture and architecture for its workability and polish.
metamorphicBahia Agate
A banded and plume agate from the Bahia state of Brazil, known for delicate dendritic and feathery inclusions.
gemstoneRegency Rose Agate
A prized plume agate with rose-pink and red feathery inclusions suspended in clear chalcedony, from the western U.S.
gemstonePaintbrush Agate
A plume agate whose inclusions form upright, bristly clusters resembling the strokes of a paintbrush.
gemstone
Landscape Agate
A translucent chalcedony agate whose mineral inclusions form miniature scenes resembling mountains, trees, deserts, and skies.
gemstone
Green Jasper
An opaque green variety of chalcedony quartz colored by iron and chlorite-group inclusions, prized as a durable carving and cabochon stone.
mineral
Feather Agate
A translucent chalcedony agate containing delicate, feather- or plume-shaped mineral inclusions that branch like soft feathers.
gemstone
Blue Jasper
An opaque blue variety of chalcedony jasper, less common than red or green forms, colored by mineral inclusions.
mineral
Blue Goldstone
A man-made glittering glass colored deep blue with cobalt and studded with tiny copper crystals that mimic a starry night sky.
gemstone
Garnet Schist
A shiny, foliated schist studded with red garnet crystals that grew during medium-grade regional metamorphism.
metamorphic
Rutile
Rutile is a major titanium ore and the famous golden needle inclusion that gives rutilated quartz its shimmering threads.
mineralTrapiche Aquamarine
A rare blue beryl showing a fixed six-spoke wheel pattern caused by impurity inclusions arranged along the crystal's growth axis.
gemstoneCloudy Obsidian
Obsidian with a hazy, cloud-like translucency caused by uneven distribution of tiny bubbles or incipient crystallites in the glass.
igneousMatte Obsidian
Obsidian with a dull, non-reflective surface from natural weathering or deliberate sandblasting/etching, rather than a distinct type of volcanic glass.
igneous
Spherulitic Obsidian
Obsidian containing spherulites — small radiating spheres of feldspar and cristobalite that crystallized within the cooling volcanic glass.
igneous
Tiger's Eye
A golden-brown chatoyant quartz with a shimmering silky band of light, formed when quartz replaces fibrous crocidolite.
gemstoneSonoran Sunset Jasper
A vivid copper-bearing Mexican stone of red cuprite and green chrysocolla that evokes a desert sunset.
mineralIce Opal
A clear, glassy, near-colorless opal resembling ice, sometimes with subtle internal flashes of play-of-color.
gemstone
Latite
The fine-grained volcanic equivalent of monzonite, an intermediate lava with nearly equal feldspars and little free quartz.
igneous