mineral: Quick Facts

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A vivid blue, textured mineral specimen of azurite displayed against a pale purple background.

Trigonal system

A schematic diagram shows the cubic crystal structure of pyrite, FeS2, with blue spheres representing ferrous iron cations (Fe2+) and yellow spheres representing sulfur anions (S-) arranged in a three-dimensional grid.

franklinite, willemite, and calcite

A cluster of pyrite crystals with a metallic gold appearance is shown, featuring both pentagonal dodecahedron shapes and striated cubic forms. Insets highlight the detailed structure of a pentagonal dodecahedron and a striated pyrite cube, with labels explaining their geometric outlines and the mineral's composition of iron and sulfur ions.

Cueva de los Cristales

Diagram showing four types of translation-free symmetry in crystals: a sixfold axis of rotation, a fourfold axis of inversion, a center of symmetry, and a mirror plane, each illustrated with a labeled purple crystal shape and explanatory text.

Three illustrated crystals are shown to demonstrate different crystal classes and symmetries: a tall, prismatic monoclinic gypsum crystal; a pointed, double-ended tetragonal wulfenite crystal; and a cubic isometric halite crystal, each labeled with its crystal class and symmetry content.

A sample of wulfenite, a mineral displaying good crystal form, from Mexico.

What Are the Seven Basic Crystal Systems?

Understand the relationship between a society's development and the management of its mineral resources

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Topics

neoformation normative mineral transformation effervescence thortveitite saprolite tungstate mineral tenacity metamictization iodate mineral soil Meteorite tektite Dust regolith Climate Equator Why Is Earth’s Axis Tilted?How Old Is Earth?What Is Earth’s Velocity?

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Key People

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Edward Daniel Clarke

English mineralogist

Georgius Agricola.

Georgius Agricola

German scholar and scientist

James D. Dana

James D. Dana

American geologist and mineralogist

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Gabriel-Auguste Daubrée

French geochemist

Lacroix

Alfred Lacroix

French mineralogist

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Victor Mordechai Goldschmidt

German crystallographer

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Axel Fredrik Cronstedt

Swedish mineralogist and chemist

Basalt sample returned by Apollo 15, from near a long sinous lunar valley called Hadley Rille. Measured at 3.3 years old.

(Bed) Rocks and (Flint) Stones

ore. iron ore minerals, rock, metal, metallic iron

Rocks, Minerals, and More Quiz