Rock & Mineral Encyclopedia

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

Ferricrete

Hard surface crust formed when iron oxides cement soil and sediment into a rusty, durable duricrust in tropical and weathered terrains.

An iron-rich sedimentary rock, often heavy and rusty-weathering, historically mined as a major source of iron ore.

An opaque, iron-rich basaltic volcanic glass formed by the rapid chilling of basalt lava, darker and denser than rhyolitic obsidian.

An opaque, iron-rich variety of microcrystalline quartz known for its deep brick-red color and ancient history as a stone of strength and grounding.

A green-and-white volcanic breccia from Vancouver Island, cemented by jasper and rich in epidote, popular as a regional lapidary stone.

A dark green-and-black stromatolite jasper patterned with swirling orbs, formed from fossilized ancient microbial colonies.

The opaque black iron-rich variety of tourmaline (schorl), forming striated prismatic crystals popular as a protective grounding stone.

A deep green-and-black stromatolitic jasper, essentially Kambaba Jasper, with circular eye patterns resembling crocodile skin.

A banded rhyolitic volcanic rock with swirling tan, red, and yellow iron-oxide layers prized as a decorative picture stone.

A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.

A sedimentary rock built from pea-sized concentric spheres called pisoids, often carbonate but sometimes iron or aluminum-rich.

A trade name for deep wine-red garnet, typically a rich pyrope-almandine stone marketed for its dramatic, fiery color.

A natural volcanic glass with rich brown and black mahogany-like swirls created by iron oxide inclusions.

A red-toned banded chalcedony colored by iron oxides, ranging from natural carnelian-like reds to heat-treated stones.