Library

Geology

Rocks, minerals, fossils, meteorites, and the formations that shaped the land you're standing on.

95

entries

5

types

Did you know

The oldest known rocks on Earth are about 4 billion years old — older than the moon's surface.

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A naturally occurring inorganic solid with a defined chemical composition.

A naturally occurring solid aggregate of minerals.

A solid material with atoms arranged in a highly ordered structure.

Preserved remains or traces of ancient organisms.

Classification of earth material by composition and properties.

Featured entries

Hand-picked highlights from the Geology library.

Hard silicate gemstone — typically yellow, also blue and pink.

A mineral in the rocks and minerals group.

Bright green olivine gemstone — August birthstone.

Hard silicate group — typically deep red, used as gem and abrasive.

Diamond is pure carbon arranged in a tetrahedral lattice — the same element that makes up graphite, but in a s…

Limestone is a sedimentary rock built almost entirely from the shells and skeletons of long-dead marine organi…

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