Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Verdite
A rich green, fuchsite-rich metamorphic rock from southern Africa, prized as a carving and ornamental stone.
metamorphic
Ironstone
An iron-rich sedimentary rock, often heavy and rusty-weathering, historically mined as a major source of iron ore.
sedimentary
Spirit Quartz
A South African quartz whose central crystal is coated in tiny druzy points, also called cactus or fairy quartz.
crystal
Sphalerite
Zinc sulfide and the chief ore of zinc, prized when transparent for its extreme fire that exceeds diamond.
mineral
Peach Tourmaline
A gentle peachy-pink tourmaline blending soft pink and orange tones, a delicate pastel variety of elbaite.
gemstone
Albitite
A pale rock made almost entirely of the sodium feldspar albite, formed by sodic magmatism or sodium metasomatism.
igneous
Golden Healer Quartz
Quartz colored or coated by golden iron oxides such as limonite or goethite, giving a warm sunlit yellow glow.
crystalContra-Luz Opal
A rare opal whose play-of-color appears only when light passes through it, glowing best when backlit or held to the light.
gemstone
Pisolite
A sedimentary rock built from pea-sized concentric spheres called pisoids, often carbonate but sometimes iron or aluminum-rich.
sedimentary
Golden Emerald
A trade name occasionally used for golden-yellow beryl (golden beryl or heliodor), the iron-colored yellow variety of the emerald mineral.
gemstone
Opal
A hydrated silica gemstone famous for its shimmering play-of-color, ranging from white and black opal to fiery orange fire opal.
gemstone
Jaspillite
A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.
metamorphic
Rutilated Quartz
Clear or smoky quartz threaded with golden to reddish needles of rutile, also poetically called Venus hair stone.
crystal
Red Garnet
The classic deep-red garnet — usually almandine or pyrope — long worn as the fiery 'carbuncle' gem and January's birthstone.
gemstone
Thulite
A pink, manganese-rich variety of zoisite used as an ornamental gemstone, often mottled with white quartz and grey matrix.
gemstone
Guano
An accumulated deposit of bird or bat droppings rich in nitrogen and phosphate, historically a prized natural fertilizer.
sedimentary
Fenite
A metasomatic rock formed when alkali-rich fluids from carbonatite or alkaline intrusions transform surrounding country rock.
metamorphic
Fossil Opal
Fossil material whose original substance has been replaced by opal, preserving ancient shapes in common or play-of-color opal.
gemstone
Tourmaline Schist
A foliated schist threaded with black tourmaline (schorl) needles, marking boron-rich metamorphic or metasomatic conditions.
metamorphic
Tourmalinated Quartz
Clear or milky quartz threaded with black needles of tourmaline (schorl), combining quartz clarity with dramatic dark inclusions.
crystal
Tibetan Quartz
Clear quartz mined in the Himalayan region, often double-terminated and containing dark hematite or carbon inclusions.
crystal
Rhyolite
A fine-grained, silica-rich volcanic rock that is the extrusive equivalent of granite, often pale, banded, or flow-textured.
igneous
Cacholong Opal
An opaque, porcelain-white common opal prized for its milky, pearl-like appearance and high porosity, often carved or beaded.
gemstone
Landscape Opal
A common opal containing dendritic or mossy mineral inclusions that form miniature landscape-like scenes inside the stone.
gemstone