Rock & Mineral Encyclopedia

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

Owyhee Blue Agate

A soft sky-blue chalcedony from the Owyhee region of Oregon and Idaho, prized for its calming, opaque powder-blue color.

A vivid Australian jasper-like silica stone in earthy reds, yellows, and purples, formed from silicified radiolarian sediment.

An agate whose layered, segmented banding resembles the jointed stalks and leaves of bamboo.

A banded chalcedony with straight, ribbon-like parallel layers, often cut across the bands for striking striped cabochons.

A dark green chalcedony speckled with blood-red spots of iron oxide, traditionally known as heliotrope.

A prized plume agate from near Carey, Idaho, showing red, pink and black feathery plumes floating in translucent chalcedony.

A richly colored red banded agate prized by lapidaries for its deep crimson-to-brown tones reminiscent of pigeon's blood.

A banded and plume agate from the Bahia state of Brazil, known for delicate dendritic and feathery inclusions.

A brown fossiliferous chalcedony packed with spiral freshwater snail shells, technically agatized fossil rock from Wyoming.

A common opal containing dendritic or mossy mineral inclusions that form miniature landscape-like scenes inside the stone.

A common opal containing moss- or fern-like mineral inclusions that resemble plants suspended in a pale silica body.

A patterned common opal with mottled, leopard-like spots and blotches, prized as an ornamental and cabochon stone.