Rock & Mineral Encyclopedia

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

Red Sandstone

Iron-stained sandstone whose red color comes from hematite coatings, formed in oxidizing desert, river, and coastal environments.

A clastic sedimentary rock made of cemented sand grains, often quartz, recording ancient beaches, deserts, and rivers.

Volcanic glass tinted red by fine iron-oxide inclusions, often blended with black to form mahogany-patterned obsidian.

Clear quartz coated with orange-red hematite, giving points a vivid tangerine color, mainly from Brazil.

A man-made glittering glass packed with tiny copper crystals, traditionally reddish-brown but also made in blue and green.

A banded combination rock of golden tiger's eye, red jasper, and metallic hematite, formed in ancient iron deposits.

A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.