Crystals of serandite, natrolite, analcime, and aegirine from Mont Saint-Hilaire, Quebec, Canada
Schist is a metamorphic rock characterized by an abundance of platy minerals. In this example, the rock has prominent sillimanite porphyroblasts as large as 3 cm.
Hübnerite, the manganese-rich end-member of the wolframite series, with minor quartz in the background
When minerals react, the products will sometimes assume the shape of the reagent; the product mineral is termed a pseudomorph of (or after) the reagent. Illustrated here is a pseudomorph of kaolinite after orthoclase. Here, the pseudomorph preserved the Carlsbad twinning common in orthoclase.
Topaz has a characteristic orthorhombic elongated crystal shape.
Contact twins, as seen in spinel
Diamond is the hardest natural material, and has a Mohs hardness of 10.
Pyrite has a metallic lustre.
Perfect basal cleavage as seen in biotite (black), and good cleavage seen in the matrix (pink orthoclase).
Galena, PbS, is a mineral with a high specific gravity.
Carnotite (yellow) is a radioactive uranium-bearing mineral.
Aegirine, an iron-sodium clinopyroxene, is part of the inosilicate subclass.
Natrolite is a mineral series in the zeolite group; this sample has a very prominent acicular crystal habit.
Muscovite, a mineral species in the mica group, within the phyllosilicate subclass
Asbestiform tremolite, part of the amphibole group in the inosilicate subclass
An example of elbaite, a species of tourmaline, with distinctive colour banding.
Epidote often has a distinctive pistachio-green colour.
Black andradite, an end-member of the orthosilicate garnet group.
Native gold. Rare specimen of stout crystals growing off of a central stalk, size 3.7 x 1.1 x 0.4 cm, from Venezuela.
Red cinnabar (HgS), a mercury ore, on dolomite.
Sphalerite crystal partially encased in calcite from the Devonian Milwaukee Formation of Wisconsin
Pink cubic halite (NaCl; halide class) crystals on a nahcolite matrix (NaHCO3; a carbonate, and mineral form of sodium bicarbonate, used as baking soda).
Gypsum desert rose

In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.

- Mineral

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International Mineralogical Association

International group of 40 national societies.

Mineralogy applies principles of chemistry, geology, physics and materials science to the study of minerals

The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species.


Olivine in cross-polarized light
Crystals of olivine embedded in iron, in a slice of Esquel, a pallasite meteorite
Figure 1: The atomic scale structure of olivine looking along the a axis. Oxygen is shown in red, silicon in pink, and magnesium/iron in blue. A projection of the unit cell is shown by the black rectangle.
Olivine altered to iddingsite within a mantle xenolith.
Open-pit mining at Sunnylvsfjorden, Hurtigruten ship passing.
Olivine grains that eroded from lava on Papakolea Beach, Hawaii
Light green olivine crystals in peridotite xenoliths in basalt from Arizona
Olivine basalt from the Moon, collected in 1971 by the crew of Apollo 15
Bright green olivine from Pakistan, showing chisel termination and silky luster
Olivine in lava from the Azores

The mineral olivine is a magnesium iron silicate with the chemical formula (Mg(2+), Fe(2+))2SiO4.

Aggregate (geology)

In the Earth sciences, aggregate has three possible meanings.

Crystal aggregate (lapis lazuli from Afghanistan)
Construction aggregate (a gravel pit in Germany)
Soil aggregate in Spain

In mineralogy and petrology, an aggregate is a mass of mineral crystals, mineraloid particles or rock particles.


Naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth.

Obsidian talus at Obsidian Dome, California
Polished snowflake obsidian, formed through the inclusion of cristobalite crystals
Glass Mountain, a large obsidian flow at Medicine Lake Volcano in California
Obsidian arrowhead
Obsidian tools from Tilkitepe, Turkey, 5th millennium BC. Museum of Anatolian Civilizations
Obsidian worked into plates and other wares by Victor Lopez Pelcastre of Nopalillo, Epazoyucan, Hidalgo. On display at the Museo de Arte Popular, Mexico City.
Raw obsidian and obsidian blades from the Mayan site of Takalik Abaj
Obsidian imported from Milos, found in Minoan Crete.
Pig carved in snowflake obsidian, 10 centimeters (4 in) long. The markings are spherulites.

The high viscosity inhibits diffusion of atoms through the lava, which inhibits the first step (nucleation) in the formation of mineral crystals.

Mohs scale of mineral hardness

Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale

The Mohs scale of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material.

Lustre (mineralogy)

Cut diamonds.
Moss opal
Satin spar variety of gypsum
Tiger's eye

Lustre (British English) or luster (American English; see spelling differences) is the way light interacts with the surface of a crystal, rock, or mineral.

Silicate mineral

Copper silicate mineral chrysocolla
Diatomaceous earth, a biogenic form of silica as viewed under a microscope. The imaged region measures approximately 1.13 by 0.69 mm.
Orthosilicate anion . The grey ball represents the silicon atom, and the red balls are the oxygen atoms.
Nesosilicate specimens at the Museum of Geology in South Dakota
Kyanite crystals (unknown scale)
Pyrosilicate anion.
Sorosilicate exhibit at Museum of Geology in South Dakota
Cyclosilicate specimens at the Museum of Geology, South Dakota
Silica family (SiO2 3D network), β-quartz.
The 3D aluminosilicate anion of synthetic zeolite ZSM-5.
Lunar ferroan anorthosite (plagioclase feldspar) collected by Apollo 16 astronauts from the Lunar Highlands near Descartes Crater
6 units {{chem2|[Si6O18]}}, beryl (red: Si, blue: O)
3 units {{chem2|[Si3O9]}}, benitoite
4 units {{chem2|[Si4O12]}}, papagoite
9 units {{chem2|[Si9O27]}}, eudialyte
6 units, double ring {{chem2|[Si6O15]}}, milarite
Inosilicate, pyroxene family, with 2-periodic single chain {{chem2|(Si2O6)}}, diopside
Inosilicate, clinoamphibole, with 2-periodic double chains {{chem2|(Si4O11)}}, tremolite
Inosilicate, unbranched 3-periodic single chain of wollastonite
Inosilicate with 5-periodic single chain, rhodonite
Inosilicate with cyclic branched 8-periodic chain, pellyite
Phyllosilicate, mica group, muscovite (red: Si, blue: O)
Phyllosilicate, single net of tetrahedra with 4-membered rings, apophyllite-(KF)-apophyllite-(KOH) series
Phyllosilicate, single tetrahedral nets of 6-membered rings, pyrosmalite-(Fe)-pyrosmalite-(Mn) series
Phyllosilicate, single tetrahedral nets of 6-membered rings, zeophyllite
Phyllosilicate, double nets with 4- and 6-membered rings, carletonite

Silicate minerals are rock-forming minerals made up of silicate groups.

Sulfide mineral


The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide (S22−) as the major anion.


Mineralogy applies principles of chemistry, geology, physics and materials science to the study of minerals
Page from Treatise on mineralogy by Friedrich Mohs (1825)
The Moon Mineralogy Mapper, a spectrometer that mapped the lunar surface
Calcite is a carbonate mineral (CaCO3) with a rhombohedral crystal structure.
Aragonite is an orthorhombic polymorph of calcite.
The perovskite crystal structure. The most abundant mineral in the Earth, bridgmanite, has this structure. Its chemical formula is (Mg,Fe)SiO3; the red spheres are oxygen, the blue spheres silicon and the green spheres magnesium or iron.
Portable Micro-X-ray fluorescence machine
Photomicrograph of olivine adcumulate from the Archaean komatiite of Agnew, Western Australia.
Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate
A color chart of some raw forms of commercially valuable metals.
A small collection of mineral samples, with cases

Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts.

Carbonate mineral

Calcite crystals from the Sweetwater Mine, Viburnum Trend District, Reynolds County, Missouri; 6.2 × 6 × 3.3 cm
Rhodochrosite, Sweet Home Mine, Alma, Colorado; 5.2 × 4.2 × 2.3 cm
Smithsonite, Silver Bill Mine, Dragoon Mts, Cochise County, Arizona; 4.8 × 4.1 × 2.4 cm
Dolomite with calcite and chalcopyrite from the Picher Field, Tri-State district, Cherokee County, Kansas; 12.0 × 9.7 × 4.3 cm
Azurite and malachite, Beaver Dam Mts, Washington County, Utah; 5.1 × 3.9 × 2.4 cm
Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate
Photomicrographs of a thin section containing carbonate vein in mica rich rock. In cross-polarized light on left, plane-polarized light on right.

Carbonate minerals are those minerals containing the carbonate ion,.