The Minerals Portal

Crystals of serandite, natrolite, analcime, and aegirine from Mont Saint-Hilaire, Quebec, Canada
Crystals of serandite, natrolite, analcime, and aegirine from Mont Saint-Hilaire, Quebec, Canada

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.

The geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or are organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks.

The concept of mineral is distinct from rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral, or may be an aggregate of two or more different types of minerals, spacially segregated into distinct phases.

Some natural solid substances without a definite crystalline structure, such as opal or obsidian, are more properly called mineraloids. If a chemical compound occurs naturally with different crystal structures, each structure is considered a different mineral species. Thus, for example, quartz and stishovite are two different minerals consisting of the same compound, silicon dioxide. (Full article...)


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. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization. (Full article...)

Refresh with new selections below (purge)

Selected articles

  • Graphite specimen
    Graphite specimen
  • The diamond crystal structure belongs to the face-centered cubic lattice, with a repeated two-atom pattern.
    The diamond crystal structure belongs to the face-centered cubic lattice, with a repeated two-atom pattern.
  • Halite from the Wieliczka salt mine, Małopolskie, Poland
    Halite from the Wieliczka salt mine, Małopolskie, Poland
  • Dolomite (white) on talc
    Dolomite (white) on talc
  • Crystal structure of  table salt (sodium in purple, chloride in green)
    Crystal structure of table salt (sodium in purple, chloride in green)
  • Brazilian trigonal hematite crystal
    Brazilian trigonal hematite crystal
  • Image 8 Chalcopyrite (/ˌkælkəˈpaɪˌraɪt, -koʊ-/ KAL-kə-PY-ryte, -⁠koh-) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black. On exposure to air, chalcopyrite tarnishes to a variety of oxides, hydroxides, and sulfates. Associated copper minerals include the sulfides bornite (Cu5FeS4), chalcocite (Cu2S), covellite (CuS), digenite (Cu9S5); carbonates such as malachite and azurite, and rarely oxides such as cuprite (Cu2O). Is rarely found in association with native copper. Chalcopyrite is a conductor of electricity. (Full article...)
  • Image 9Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They are tetrahedral, three dimensional, crystalline minerals of aluminosilicate earth metals and belong to the acidic catalysts. The term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material zeolite, from the Greek ζέω (zéō), meaning "to boil" and λίθος (líthos), meaning "stone".Zeolites occur naturally but are also produced industrially on a large scale. , 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure that is obtained is examined by the International Zeolite Association Structure Commission and receives a three letter designation. (Full article...)
    Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They are tetrahedral, three dimensional, crystalline minerals of aluminosilicate earth metals and belong to the acidic catalysts. The term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material zeolite, from the Greek ζέω (zéō), meaning "to boil" and λίθος (líthos), meaning "stone".

    Zeolites occur naturally but are also produced industrially on a large scale. , 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure that is obtained is examined by the International Zeolite Association Structure Commission and receives a three letter designation. (Full article...)
  • Amethyst cluster from Magaliesburg, South Africa.
    Amethyst cluster from Magaliesburg, South Africa.
  • Image 11 Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common endmembers is written as Ca10(PO4)6(OH,F,Cl)2, and the crystal unit cell formulae of the individual minerals are written as Ca10(PO4)6(OH)2, Ca10(PO4)6F2 and Ca10(PO4)6Cl2. The mineral was named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. Apatite is often mistaken for other minerals. This tendency is reflected in the mineral
  • Intergrowth of lustrous, cubic crystals of pyrite, with some surfaces showing characteristic striations, from Huanzala mine, Ancash, Peru. Specimen size: 7.0 × 5.0 × 2.5 cm
    Intergrowth of lustrous, cubic crystals of pyrite, with some surfaces showing characteristic striations, from Huanzala mine, Ancash, Peru. Specimen size: 7.0 × 5.0 × 2.5 cm
  • Image 13 Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. A massive fine-grained white or lightly tinted variety of gypsum, called alabaster, has been used for sculpture by many cultures including Ancient Egypt, Mesopotamia, Ancient Rome, the Byzantine Empire, and the Nottingham alabasters of Medieval England. Gypsum also crystallizes as translucent crystals of selenite. It forms as an evaporite mineral and as a hydration product of anhydrite. The Mohs scale of mineral hardness defines gypsum as hardness value 2 based on scratch hardness comparison. (Full article...)
  • Image 14 Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especially polarization optics, for longer visible and infrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum. Rutile derives its name from the Latin rutilus (
  • Mineralogy applies principles of chemistry, geology, physics and materials science to the study of minerals
    Mineralogy applies principles of chemistry, geology, physics and materials science to the study of minerals
  • A sample of andesite (dark groundmass) with amygdaloidal vesicles filled with zeolite. Diameter of view is 8 cm.
    A sample of andesite (dark groundmass) with amygdaloidal vesicles filled with zeolite. Diameter of view is 8 cm.
  • Image 17 Cinnabar (/ˈsɪnəˌbɑːr/) or cinnabarite (/sɪnəˈbɑːraɪt/), from the Ancient Greek: κιννάβαρι (kinnabari), is the bright scarlet to brick-red form of mercury(II) sulfide (HgS). It is the most common source ore for refining elemental mercury, and is the historic source for the brilliant red or scarlet pigment termed vermilion and associated red mercury pigments. Cinnabar generally occurs as a vein-filling mineral associated with recent volcanic activity and alkaline hot springs. The mineral resembles quartz in symmetry and in its exhibiting birefringence. Cinnabar has a mean refractive index near 3.2, a hardness between 2.0 and 2.5, and a specific gravity of approximately 8.1. The color and properties derive from a structure that is a hexagonal crystalline lattice belonging to the trigonal crystal system, crystals that sometimes exhibit twinning. Cinnabar has been used for its color since antiquity in the Near East, including as a rouge-type cosmetic, in the New World since the Olmec culture, and in China since as early as the Yangshao culture, where it was used in coloring stoneware. Associated modern precautions for use and handling of cinnabar arise from the toxicity of the mercury component, which was recognized as early as ancient Rome. (Full article...)
  • Green fluorite with prominent cleavage
    Green fluorite with prominent cleavage
  • Image 19 Micas (/ˈmaɪkəz/ MY-kəz) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. It is particularly prominent in many granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites. Micas are used in products such as drywalls, paints, fillers, especially in parts for automobiles, roofing and shingles, as well as in electronics. The mineral is used in cosmetics to add "shimmer" or "frost." (Full article...)
  • A rich seam of iridescent opal encased in matrix
    A rich seam of iridescent opal encased in matrix
  • A rock containing three crystals of pyrite (FeS2). The crystal structure of pyrite is primitive cubic, and this is reflected in the cubic symmetry of its natural crystal facets.
    A rock containing three crystals of pyrite (FeS2). The crystal structure of pyrite is primitive cubic, and this is reflected in the cubic symmetry of its natural crystal facets.
  • A crystalline solid: atomic resolution image of strontium titanate. Brighter spots are columns of strontium atoms and darker ones are titanium-oxygen columns.
    A crystalline solid: atomic resolution image of strontium titanate. Brighter spots are columns of strontium atoms and darker ones are titanium-oxygen columns.
  • The Needles, situated off the Isle of Wight, are part of the extensive Southern England Chalk Formation.
    The Needles, situated off the Isle of Wight, are part of the extensive Southern England Chalk Formation.
  • Image 24 Borax is a salt (ionic compound), a hydrated borate of sodium, with chemical formula Na2H20B4O17 often written Na2B4O7·10H2O. It is a colorless crystalline solid, that dissolves in water to make a basic solution. It is commonly available in powder or granular form, and has many industrial and household uses, including as a pesticide, as a metal soldering flux, as a component of glass, enamel, and pottery glazes, for tanning of skins and hides, for artificial aging of wood, as a preservative against wood fungus, and as a pharmaceutic alkalizer. In chemical laboratories, it is used as a buffering agent. The compound is often called sodium tetraborate decahydrate, but that name is not consistent with its structure. The anion is not tetraborate [B4O7]2− but tetrahydroxy tetraborate [B4O5(OH)4]2−, so the more correct formula should be Na2B4O5(OH)4·8H2O. Informally, the product is often called sodium borate decahydrate or just sodium borate. The terms tincal /ˈtɪŋkəl/ "tinkle" and tincar /ˈtɪŋkər/ "tinker" refer to native borax, historically mined from dry lake beds in various parts of Asia. (Full article...)
  • Image 25 Garnets ( /ˈɡɑːrnɪt/) are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different species are pyrope, almandine, spessartine, grossular (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite. The garnets make up two solid solution series: pyrope-almandine-spessartine (pyralspite), with the composition range [Mg,Fe,Mn]3Al2(SiO4)3; and uvarovite-grossular-andradite (ugrandite), with the composition range Ca3[Cr,Al,Fe]2(SiO4)3. (Full article...)

Selected mineralogist

Related portals

Get involved

For editor resources and to collaborate with other editors on improving Wikipedia's Minerals-related articles, see WikiProject Rocks and minerals.

General images

The following are images from various mineral-related articles on Wikipedia.
  • Image 1Gypsum desert rose (from Mineral)
    Gypsum desert rose (from Mineral)
  • Image 2Black andradite, an end-member of the orthosilicate garnet group. (from Mineral)
    Black andradite, an end-member of the orthosilicate garnet group. (from Mineral)
  • Image 3Galena, PbS, is a mineral with a high specific gravity. (from Mineral)
    Galena, PbS, is a mineral with a high specific gravity. (from Mineral)
  • Image 4Pyrite (from Lustre (mineralogy))
    Pyrite (from Lustre (mineralogy))
  • Image 5Asbestiform tremolite, part of the amphibole group in the inosilicate subclass (from Mineral)
    Asbestiform tremolite, part of the amphibole group in the inosilicate subclass (from Mineral)
  • Image 6Hübnerite, the manganese-rich end-member of the wolframite series, with minor quartz in the background (from Mineral)
    Hübnerite, the manganese-rich end-member of the wolframite series, with minor quartz in the background (from Mineral)
  • Image 7Pyrite has a metallic lustre. (from Mineral)
    Pyrite has a metallic lustre. (from Mineral)
  • Image 8Contact twins, as seen in spinel (from Mineral)
    Contact twins, as seen in spinel (from Mineral)
  • Image 9Red cinnabar (HgS), a mercury ore, on dolomite. (from Mineral)
    Red cinnabar (HgS), a mercury ore, on dolomite. (from Mineral)
  • Image 10Sphalerite crystal partially encased in calcite from the Devonian Milwaukee Formation of Wisconsin (from Mineral)
    Sphalerite crystal partially encased in calcite from the Devonian Milwaukee Formation of Wisconsin (from Mineral)
  • Image 11Perfect basal cleavage as seen in biotite (black), and good cleavage seen in the matrix (pink orthoclase). (from Mineral)
    Perfect basal cleavage as seen in biotite (black), and good cleavage seen in the matrix (pink orthoclase). (from Mineral)
  • Image 12Muscovite, a mineral species in the mica group, within the phyllosilicate subclass (from Mineral)
    Muscovite, a mineral species in the mica group, within the phyllosilicate subclass (from Mineral)
  • Image 13Native gold. Rare specimen of stout crystals growing off of a central stalk, size 3.7 x 1.1 x 0.4 cm, from Venezuela. (from Mineral)
    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. (from Mineral)
  • Image 14Pink cubic halite (NaCl; halide class) crystals on a nahcolite matrix (NaHCO3; a carbonate, and mineral form of sodium bicarbonate, used as baking soda). (from Mineral)
    Pink cubic halite (NaCl; halide class) crystals on a nahcolite matrix (NaHCO3; a carbonate, and mineral form of sodium bicarbonate, used as baking soda). (from Mineral)
  • Image 15Crystals of serandite, natrolite, analcime, and aegirine from Mont Saint-Hilaire, Quebec, Canada (from Mineral)
    Crystals of serandite, natrolite, analcime, and aegirine from Mont Saint-Hilaire, Quebec, Canada (from Mineral)
  • Image 16Schist 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 (1.2 in). (from Mineral)
    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 (1.2 in). (from Mineral)
  • Image 17Diamond is the hardest natural material, and has a Mohs hardness of 10. (from Mineral)
    Diamond is the hardest natural material, and has a Mohs hardness of 10. (from Mineral)
  • Image 18When 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. (from Mineral)
    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. (from Mineral)
  • Image 19Natrolite is a mineral series in the zeolite group; this sample has a very prominent acicular crystal habit. (from Mineral)
    Natrolite is a mineral series in the zeolite group; this sample has a very prominent acicular crystal habit. (from Mineral)
  • Image 20Carnotite (yellow) is a radioactive uranium-bearing mineral. (from Mineral)
    Carnotite (yellow) is a radioactive uranium-bearing mineral. (from Mineral)
  • Image 21Topaz has a characteristic orthorhombic elongated crystal shape. (from Mineral)
    Topaz has a characteristic orthorhombic elongated crystal shape. (from Mineral)
  • Image 22Aegirine, an iron-sodium clinopyroxene, is part of the inosilicate subclass. (from Mineral)
    Aegirine, an iron-sodium clinopyroxene, is part of the inosilicate subclass. (from Mineral)
  • Image 23An example of elbaite, a species of tourmaline, with distinctive colour banding. (from Mineral)
    An example of elbaite, a species of tourmaline, with distinctive colour banding. (from Mineral)
  • Image 24Epidote often has a distinctive pistachio-green colour. (from Mineral)
    Epidote often has a distinctive pistachio-green colour. (from Mineral)
  • Image 25Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale (from Mohs scale of mineral hardness)
    Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale (from Mohs scale of mineral hardness)

Did you know ...?

The Ram

Subcategories

Category puzzle
Select [►] to view subcategories

Topics

Associated Wikimedia

The following Wikimedia Foundation sister projects provide more on this subject:

References

Discover Wikipedia using portals

Purge server cache