Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Rubellite
The red to raspberry-pink variety of tourmaline, prized for its vivid ruby-like color that holds under both daylight and artificial light.
gemstone
Crimson Obsidian
A deep red glass sold as obsidian; vivid uniform crimson material is usually manufactured glass rather than natural volcanic obsidian.
igneous
Cuprite
Cuprite is a deep red copper oxide and an important secondary copper ore, prized for its rare ruby-red gem crystals.
mineral
Raspberry Garnet
A vivid pinkish-red rhodolite garnet named for its raspberry color, a bright pyrope-almandine blend popular in jewelry.
gemstone
Chalcocite
A dark gray copper sulfide that is one of the richest copper ores, prized by collectors when found as rare sharp crystals.
mineral
Cape Ruby
Cape Ruby is a deep red pyrope garnet from South African diamond deposits, prized as an affordable, fiery alternative to ruby.
gemstone
Spinel
A durable magnesium aluminum oxide gem that occurs in many colors and was long mistaken for ruby.
gemstone
Erythrite
A soft pink to crimson hydrated cobalt arsenate, famous as cobalt bloom that signals nearby cobalt ores.
mineral
Ruby
The red, chromium-colored variety of corundum, prized as one of the most valuable colored gemstones and second only to diamond in hardness.
gemstone
Raspberry Tourmaline
A vivid raspberry-pink to pinkish-red elbaite tourmaline, a bright, cheerful member of the rubellite family colored by manganese.
gemstone
Enhydro Quartz
Quartz containing a sealed pocket of ancient water, often with a mobile air bubble that moves when the crystal is tilted.
crystal
Strawberry Garnet
A bright strawberry-red garnet, typically an almandine-pyrope blend prized for its juicy, lively red color in jewelry.
gemstone
Bixbite
An old trade name for red beryl, the extremely rare manganese-colored beryl from Utah, now largely replaced by the term red beryl.
gemstone
Zincite
A rare zinc oxide best known for its deep red to orange color, classically from Franklin, New Jersey, and as colorful man-made crystals.
mineral
Sandstone
A clastic sedimentary rock made of cemented sand grains, often quartz, recording ancient beaches, deserts, and rivers.
sedimentary
Montana Garnet
Montana Garnet is red almandine recovered from Montana placer gravels, often alongside the state's famous sapphires.
gemstone
Cherry Obsidian
A vivid cherry-red glass sold as obsidian; the bright transparent red color is manufactured, as natural obsidian only shows dull red-brown mahogany tones.
igneous
Siberite
A historic name for the red-violet to purplish lithium tourmaline first prized from Siberia, closely tied to the rubellite variety.
gemstone
Jasper
An opaque, often colorfully patterned variety of chalcedony quartz, popular for tumbling, carving, and jewelry.
mineral
Carnelian
A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.
gemstone
Flame Jasper
A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.
mineral
Sherry Tourmaline
A warm sherry-brown to orange-brown tourmaline, usually magnesium-rich dravite, named for its rich fortified-wine color.
gemstone
Burgundy Tourmaline
A deep wine-red to maroon tourmaline colored by manganese, a rich darker-toned member of the red-pink rubellite family.
gemstone
Pipestone
A soft, fine-grained red metamorphosed claystone, sacred to many Native American peoples and carved into ceremonial pipes.
metamorphic