Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Yellow Jasper
An opaque yellow-to-golden variety of jasper, an iron-stained microcrystalline quartz prized for warm color and durable polish.
gemstone
Amethyst
The purple variety of quartz, colored by iron and natural irradiation, prized as the classic violet birthstone of February.
crystal
Picture Jasper
An opaque brown chalcedony whose iron-stained banding mimics deserts, dunes, and distant mountain skylines.
mineral
Carnelian
A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.
gemstoneFlame Jasper
A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.
mineralDendritic Jasper
A pale jasper threaded with black, fern-like mineral dendrites that mimic plants, trees, and frost despite being inorganic.
mineral
Porcelanite
A hard, fine-grained siliceous rock with a dull porcelain-like texture, intermediate between soft diatomite and dense chert.
sedimentary
Radiolarite
A hard, fine-grained siliceous rock built from the microscopic silica skeletons of radiolarians, often forming colorful ribbon-banded cherts.
sedimentaryApricot Agate
A soft peachy-orange variety of banded chalcedony, naturally iron-tinted or dyed, popular for warm-toned beads and jewelry.
gemstoneButterstone Jasper
A soft-toned cream-to-butterscotch jasper colored by iron oxides, prized by lapidaries for its smooth, even, opaque finish.
gemstone
Ruin Marble
A fractured fine-grained limestone whose iron-stained crack networks form natural scenes resembling ruined cities and landscapes.
sedimentary
Mustard Jasper
A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.
gemstoneDragon Blood Jasper
A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.
metamorphicSard
A brownish-red to deep brown variety of chalcedony, closely related to carnelian but darker, colored by iron oxides.
mineral
Brecciated Jasper
A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.
sedimentaryBird's Eye Jasper
A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.
mineral
Blood Agate
A deep red banded agate colored by iron oxides, valued as a vivid red lapidary and jewelry stone.
gemstone
Pumpkin Obsidian
An orange-to-rust colored variety of natural volcanic glass whose warm tone comes from iron oxide staining within the obsidian.
igneous
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
Bloodstone Jasper
A dark green jasper-chalcedony speckled with red iron-oxide spots, classically known as bloodstone or heliotrope.
mineralPrase
An old name for a dull leek-green variety of quartz or chalcedony colored by green mineral inclusions, historically called mother of emerald.
crystal
Chalcedony
A waxy, translucent microcrystalline form of quartz that serves as the parent group for agate, jasper, carnelian, and onyx.
mineral
Ametrine
A natural bicolor quartz that combines purple amethyst and golden citrine in a single crystal.
crystal
Citrine
The golden-yellow variety of quartz, ranging from pale lemon to deep madeira amber, often produced by heating amethyst.
gemstone