Rock & Mineral Encyclopedia

Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.

Sulfur

A bright yellow native element mineral that forms around volcanic vents and hot springs and burns with a blue flame.

A dense, soft, intensely yellow native metal valued for millennia in coinage, jewelry, and electronics.

A soft, reddish native metal with excellent conductivity, mined for wiring, plumbing, and alloys like bronze and brass.

A dense, durable, silvery-white precious metal that resists corrosion, used in fine jewelry and catalytic converters.

Precious opal from Brazil, especially the Pedro II area of Piaui, known for bright, often stable crystal and white opal.

A soft, lustrous white native metal with the highest electrical conductivity, used in jewelry, coinage, and industry.

Precious opal from Spencer, Idaho, occurring in thin colorful seams that are typically cut into triplets.

Abundant banded chalcedony from southern Brazil, the world's main source of agate slices and dyed agate products.

Montana Garnet is red almandine recovered from Montana placer gravels, often alongside the state's famous sapphires.

Precious opal from Honduras occurring in a dark volcanic matrix, where bright flecks of color flash against a natural black basalt background.

A soft, fine-grained red metamorphosed claystone, sacred to many Native American peoples and carved into ceremonial pipes.

Rounded nodules of translucent obsidian, named after a Native American legend, that glow smoky brown when held to light.

A heavy, lead-grey metallic mineral with perfect cubic cleavage, galena is the world's main ore of lead and often carries silver.

An unusually pure, transparent-to-translucent obsidian with few inclusions; truly water-clear specimens are rare in nature.