Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Orange Calcite
A soft, glowing orange variety of calcite colored by iron oxides, popular as tumbled stones and known for fizzing in acid.
mineral
Red Sandstone
Iron-stained sandstone whose red color comes from hematite coatings, formed in oxidizing desert, river, and coastal environments.
sedimentary
Calcite
An extremely common calcium carbonate mineral that comes in nearly every color and shows strong double refraction in clear crystals.
mineral
Siderite
Siderite is an iron carbonate ore, a brown rhombohedral mineral of the calcite group found in sediments and veins.
mineral
Blue Calcite
A soft, soothing powder-blue variety of calcite, a common calcium carbonate mineral often sold as gentle tumbled stones.
mineral
Green Calcite
A soft mint-to-apple-green variety of calcite, a common calcium carbonate mineral popular as soothing tumbled stones.
mineral
Honey Calcite
A warm golden-to-amber variety of calcite, a soft calcium carbonate mineral valued for its honeyed glow and easy carving.
mineral
Mahogany Obsidian
A natural volcanic glass with rich brown and black mahogany-like swirls created by iron oxide inclusions.
igneous
Bumblebee Jasper
A vivid yellow-and-black banded stone from Indonesian volcanic vents, colored by sulfur, arsenic minerals and iron oxides, not true jasper.
sedimentary
Bog Iron
A soft, porous iron ore of limonite and goethite that forms in wetlands and bogs, historically the first iron source for many cultures.
sedimentary
Tiger Iron
A banded combination rock of golden tiger's eye, red jasper, and metallic hematite, formed in ancient iron deposits.
metamorphic
Ironstone
An iron-rich sedimentary rock, often heavy and rusty-weathering, historically mined as a major source of iron ore.
sedimentary
Picture Jasper
An opaque brown chalcedony whose iron-stained banding mimics deserts, dunes, and distant mountain skylines.
mineral
Banded Iron Formation
Ancient chemically deposited rock of alternating iron-oxide and silica bands recording Earth's early oxygenation and a major iron ore source.
sedimentary
Ruin Marble
A fractured fine-grained limestone whose iron-stained crack networks form natural scenes resembling ruined cities and landscapes.
sedimentary
Pumpkin Obsidian
An orange-to-rust colored variety of natural volcanic glass whose warm tone comes from iron oxide staining within the obsidian.
igneous
Fossiliferous Limestone
Calcium-carbonate sedimentary rock packed with visible fossils, recording ancient marine life within an easily scratched, fizzing matrix.
sedimentary
Yellow Jasper
An opaque yellow-to-golden variety of jasper, an iron-stained microcrystalline quartz prized for warm color and durable polish.
gemstone
Brecciated Jasper
A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.
sedimentary
Starry Night Jasper
A dark jasper trade stone speckled with pale flecks resembling a starry night sky, valued for its cosmic appearance.
mineral
Crocodile Jasper
A deep green-and-black stromatolitic jasper, essentially Kambaba Jasper, with circular eye patterns resembling crocodile skin.
mineral
Royal Sahara Jasper
A warm desert-toned picture jasper trade stone with sandy tan, gold, and brown swirls evoking Saharan dunes.
mineral
Biggs Jasper
A classic Oregon picture jasper showing layered tan, brown, and blue-grey scenes resembling desert landscapes and canyons.
mineral
Golden Healer Quartz
Quartz colored or coated by golden iron oxides such as limonite or goethite, giving a warm sunlit yellow glow.
crystal