Rock & Mineral Encyclopedia

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

Geode

A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.

A soft pink banded chalcedony, occurring naturally in delicate hues and also commonly produced by dyeing.

A nodular rhyolite geode-like ball whose plain exterior hides a star-shaped agate or chalcedony core when cut.

A finely banded agate from Botswana known for delicate parallel layers of grey, pink, and white.

A creamy pink-and-white chalcedony from Madagascar containing flower-like plume inclusions that resemble blossoms suspended in stone.

A warmly colored chalcedony agate with reds, oranges, golds, and pinks that blend like the glowing bands of a sunset sky.

A prized plume agate with rose-pink and red feathery inclusions suspended in clear chalcedony, from the western U.S.

Plume and fortification agate from the famous Woodward Ranch near Alpine, Texas, known for red and pink plumes.

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

A chalcedony with a distinctive scaly, reptile-skin surface texture, typically in pale tan, pink, and gray tones.

A multicolored orbicular chalcedony from Madagascar famous for its circular eye-like orbs in greens, pinks, whites, and yellows.