Rock & Mineral Encyclopedia

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

Mocha Agate

A pale translucent chalcedony threaded with brown-black manganese and iron dendrites that mimic tiny ferns, mosses or landscapes.

An opaque, often colorfully patterned variety of chalcedony quartz, popular for tumbling, carving, and jewelry.

An affordable multicolored banded and mossy chalcedony from India, common in tumbled stones, beads, and meditation pieces.

Glacially transported banded agates found along Lake Huron's shores, typically small, frosted pebbles with red-orange iron banding.

Glacially deposited banded agates found along Lake Michigan beaches, small waterworn pebbles with concentric red and grey banding.

A chalcedony agate containing hollow or mineral-filled tubes that appear as rods, circles, or pipes depending on the angle of the cut.