Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Shattuckite
A rare deep-blue copper silicate mineral, often fibrous or massive, named for the Shattuck Mine in Arizona and prized by collectors.
mineralSard
A brownish-red to deep brown variety of chalcedony, closely related to carnelian but darker, colored by iron oxides.
mineral
Moss Agate
A translucent chalcedony filled with green or brown dendritic mineral inclusions that resemble moss, foliage, or landscapes.
gemstone
Blue Sapphire
The blue gem variety of corundum, prized for its rich color, extreme hardness, and brilliance second only to diamond.
gemstone
Claystone
A very fine-grained sedimentary rock made mostly of clay minerals, smooth to the touch and lacking the gritty feel of siltstone.
sedimentary
Amethyst
The purple variety of quartz, colored by iron and natural irradiation, prized as the classic violet birthstone of February.
crystal
Malachite
A vivid green copper carbonate mineral famous for swirling concentric bands, used as an ore of copper and an ornamental gemstone.
mineral
Travertine
A banded, porous limestone deposited by mineral springs, prized as a warm-toned natural building and tile stone.
sedimentary
Shale
The most common sedimentary rock, a fissile mudrock of compacted clay and silt that splits into thin layers.
sedimentary
Rose Quartz
The soft pink, usually cloudy variety of quartz colored by trace titanium or microscopic inclusions, popular for carvings and beads.
crystal
Serpentinite
A green, often mottled metamorphic rock formed by the hydration of mantle rocks, soft and waxy with a smooth, slippery feel.
metamorphic
Cassiterite
Tin oxide and the principal ore of tin, a dense, hard mineral mined since the Bronze Age for tin metal.
mineral
Hessonite Garnet
The cinnamon-to-honey colored variety of grossular garnet, prized in jewelry and revered as the gem 'gomed' in Vedic astrology.
gemstone
Azurite
A deep blue copper carbonate mineral that forms in oxidized copper deposits, often alongside green malachite.
mineralHoney Opal
A warm golden-to-amber opal ranging from translucent common opal to precious stones that flash play-of-color over a honey body.
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
Mustard Jasper
A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.
gemstone
Aventurine Feldspar
A feldspar, better known as sunstone, that sparkles with metallic glints from tiny mineral platelets, an effect called aventurescence.
gemstoneButterstone Jasper
A soft-toned cream-to-butterscotch jasper colored by iron oxides, prized by lapidaries for its smooth, even, opaque finish.
gemstone
Shungite
A rare black carbon-rich rock from Russia, noted for containing fullerenes and ranging from dull mineralized stone to lustrous noble shungite.
sedimentary
Orange Calcite
A soft, glowing orange variety of calcite colored by iron oxides, popular as tumbled stones and known for fizzing in acid.
mineral
Serpentine
A group of green magnesium silicate minerals with a smooth, waxy feel, often carved and sometimes sold as imitation jade.
mineral
Blue Quartz
A naturally blue quartz colored by tiny mineral inclusions such as dumortierite or scattered rutile and tourmaline fibers.
crystal
Dumortierite Quartz
Quartz colored blue by inclusions of the mineral dumortierite, giving a denim-like blue ornamental stone harder than dumortierite alone.
gemstone