Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Quartzite
An extremely hard metamorphic rock formed from sandstone, made of fused quartz grains that break across rather than between the grains.
metamorphic
Blue Goldstone
A man-made glittering glass colored deep blue with cobalt and studded with tiny copper crystals that mimic a starry night sky.
gemstoneQuartz Arenite
A clean, mature sandstone made almost entirely of quartz grains, representing extreme weathering, sorting, and recycling of sediment.
sedimentary
Goldstone
A man-made glittering glass packed with tiny copper crystals, traditionally reddish-brown but also made in blue and green.
crystalSesame Jasper
A finely speckled pale jasper trade stone named for its sesame-seed-like flecks, closely related to Kiwi Jasper.
mineralKiwi Jasper
A speckled green-and-black stone resembling kiwi fruit, technically a quartz-amazonite aggregate rather than true jasper.
mineral
Bumblebee Jasper
A vivid yellow-and-black banded stone from Indonesian volcanic vents, colored by sulfur, arsenic minerals and iron oxides, not true jasper.
sedimentary
Ceylon Garnet
Ceylon Garnet is a historic trade name for fine red almandine (and hessonite) garnet from the gem gravels of Sri Lanka.
gemstoneMontana Garnet
Montana Garnet is red almandine recovered from Montana placer gravels, often alongside the state's famous sapphires.
gemstone
Cleavelandite
A striking platy, blade-like variety of albite feldspar that grows in fanned aggregates of thin white crystals within granite pegmatites.
mineralColdwater Agate
A glacially transported agate found in Midwestern gravels, named for the Coldwater area, showing banded chalcedony patterns.
gemstonePink Opal
A soft pink common opal, most famously from Peru, valued for its gentle pastel color rather than play-of-color.
gemstoneMint Opal
A soft mint-green variety of common opal, usually opaque and colored by trace copper or nontronite inclusions rather than play-of-color.
gemstone
Peruvian Pink Opal
A soft pink common opal from the Peruvian Andes, prized for its opaque rosy color rather than play-of-color.
gemstonePeruvian Blue Opal
A translucent common opal from the Andes prized for its serene blue to blue-green color, usually cut into cabochons and beads.
gemstone
Granite
A coarse-grained, speckled intrusive rock built from quartz, feldspar, and mica, forming the bedrock of the continents.
igneous
Sagenite Agate
A chalcedony agate filled with radiating needle-like mineral inclusions, prized for its starburst and spray patterns.
gemstone
Mali Garnet
A rare grossular-andradite blend ('grandite') from Mali, prized for its high brilliance and golden-green to yellow color.
gemstoneOrca Agate
A bold black-and-white banded chalcedony named for its orca-like coloring, popular as carvings and statement jewelry.
gemstone
Blue Opal
A soft blue common opal, famously from Peru, valued for its serene sky-to-teal color rather than play-of-color.
gemstone
Lavender Opal
A pastel purple variety of common opal, valued for its gentle lilac body color rather than any play-of-color.
gemstone
Black Garnet
An opaque black garnet — typically titanium-bearing melanite andradite — historically cut for mourning and Victorian jewelry.
gemstone
Ugrandite Garnet
Ugrandite is the calcium garnet series uniting uvarovite, grossular, and andradite, including tsavorite and the fiery demantoid.
mineral
Demantoid Garnet
A rare green andradite garnet famed for fire exceeding diamond and distinctive horsetail inclusions in Russian stones.
gemstone