Explore the geological database

Every entry is a single scientific record, so a variety such as amethyst appears under its parent mineral, quartz, without duplicate pages. Unknown measurements are left blank rather than guessed.

Minerals

6319

Mineral species and common varieties.

Rocks

Igneous, sedimentary and metamorphic rocks.

Crystals

Crystal habits and crystalline specimens.

Gemstones

Gem materials and ornamental stones.

Fossils

Fossil taxa and preservation types.

Meteorites

1147

Meteorite falls, finds and groups.

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Blue minerals Green crystals Hardest minerals

Featured specimens

Gemstone

Ruby

Formula: Al2O3
Mohs: 9
Colour: Red

Mineral

Quartz

Formula: SiO2
Mohs: 7
Colour: Colourless, white, purple, pink, brown, black

Rock

Granite

Mohs: 6–7
Colour: Light coloured with dark speckles

Gemstone

Emerald

Formula: Be3Al2Si6O18
Mohs: 7.5–8
Colour: Green

Mineral

Calcite

Formula: CaCO3
Mohs: 3
Colour: Colourless, white, many tints

Mineral

Amethyst

Formula: SiO2
Mohs: 7
Colour: Purple

Fossil

Trilobite

Gemstone

Turquoise

Formula: CuAl6(PO4)4(OH)8·4H2O
Mohs: 5–6
Colour: Blue to green