Mineral
Mineral - Associations, Phase Equilibrium, Crystallization: The preceding sections provided an overview of major mineral groups but did not treat minerals as part of assemblages in rock types nor discuss the experimental study of minerals and rock occurrences. Petrology, the scientific study of rocks, is concerned largely with identifying individual minerals in rocks, along …
Lazulite | Manganese, Phosphate & Magnesium | Britannica
Lazulite, phosphate mineral, a basic magnesium and aluminum phosphate [MgAl2 (PO4)2(OH)2], that often occurs as blue, glassy crystals, grains, or masses in granite pegmatites, aluminous metamorphic rocks and quartzites, and quartz veins. It is found in Werfen, Austria; Västarå, Sweden; Mocalno,
Mineral
Mineral - Crystal Structures, Chemical Compounds: The external morphology of a mineral is an expression of the fundamental internal architecture of a crystalline substance—i.e., its crystal structure. The crystal structure is the three-dimensional, regular (or ordered) arrangement of chemical units (atoms, ions, and anionic groups in inorganic materials; …
Formation of minerals | Britannica
Although most minerals are chemical compounds, a small number (e.g., sulfur, copper, gold) are elements. Minerals combine with each other to form rocks. For example, granite consists of the minerals feldspar, quartz, mica, and amphibole in varying amounts. Rocks are generally, therefore, an intergrowth of various minerals.
quartz summary | Britannica
quartz, Second most abundant mineral (after feldspar) in the Earth's crust, present in many rocks. Quartz, which consists of silica, or silicon dioxide (SiO 2), has great economic importance. Many varieties are gemstones, including amethyst, citrine, smoky quartz, and rose quartz. Sandstone, composed mainly of quartz, is an important building ...
Mineral
Mineral - Oxides, Hydroxides, Compounds: These classes consist of oxygen-bearing minerals; the oxides combine oxygen with one or more metals, while the hydroxides are characterized by hydroxyl (OH)– groups. The oxides …
Mineral | Types & Uses | Britannica
Since a mineral has a definite composition, it can be expressed by a specific chemical formula.Quartz (silicon dioxide), for instance, is rendered as SiO 2, because the elements silicon (Si) and oxygen (O) are its only constituents and they invariably appear in a 1:2 ratio. The chemical makeup of most minerals is not as well defined as that of quartz, which is a …
Mineral
Mineral - Chemical Bonding, Structure, Properties: Electrical forces are responsible for the chemical bonding of atoms, ions, and ionic groups that constitute crystalline solids. The physical and chemical properties of minerals …
Metamorphic rock
Metamorphic rock - Zeolite Facies, Minerals, Textures: In the zeolite facies, sediments and volcanic debris show the first major response to burial. Reactions are often not complete, and typical metamorphic fabrics may be poorly developed or not developed at all. This is the facies of burial metamorphism. The zeolite facies was first described from southern New …
Smoky quartz | Healing, Metaphysical & Grounding | Britannica
smoky quartz, very common coarse-grained variety of the silica mineral quartz that ranges in colour from nearly black through smoky brown. No distinct boundary exists between smoky and colourless quartz. Its abundance causes it to be worth considerably less than either amethyst or citrine. Heating bleaches the stone, the colour sometimes passing through yellow; these yellow …
Plasma | Ionized Gases, Electron Density & Magnetic Fields | Britannica
plasma, in mineralogy, semitranslucent, microgranular or microfibrous, semiprecious variety of the silica mineral chalcedony.Its colour, various shades of green, is due to disseminated silicate particles of different kinds—e.g., amphibole or chlorite. Other properties are those of quartz.Plasma often has nodules of gray quartz or red jasper (bloodstone) throughout its mass.
The formation of sand from quartz | Britannica
Well, much of the world's sand is made out of the same stuff, tiny crystals of the mineral quartz, which is made out of silica and oxygen, the two most common elements in Earth's crust. And as you'll know if you've ever been through the crust of a sandwich that had sand in it, …
Mineral
Mineral - Crystal Habit, Aggregation: The external shape (habit) of well-developed crystals can be visually studied and classified according to the various crystal systems that span the 32 crystal classes. The majority of crystal occurrences, however, are not part of well-formed single crystals but are found as crystals grown together in aggregates. Examples of some …
Amethyst | Purple Quartz, Healing Properties, …
Amethyst, a transparent, coarse-grained variety of the silica mineral quartz that is valued as a semiprecious gem for its violet colour. Its physical properties are those of quartz, but it contains more iron oxide (Fe2O3) than any other variety …
Pyrite | Properties & Facts | Britannica
Pyrite, a naturally occurring iron disulfide mineral. The name comes from the Greek word pyr, 'fire,' because pyrite emits sparks when struck by metal. Pyrite is called fool's gold; to the novice its color is deceptively similar to …
Mineral
Mineral - Hardness, Mohs Scale, Crystalline: Hardness (H) is the resistance of a mineral to scratching. It is a property by which minerals may be described relative to a standard scale of 10 minerals known as the Mohs scale of hardness. The degree of hardness is determined by observing the comparative ease or difficulty with which one mineral is scratched by another …
Quartz | Earth Sciences Museum | University of …
Quartz is our most common mineral. Quartz is made of the two most abundant chemical elements on Earth: oxygen and silicon. Atoms of oxygen and silicon join together as tetrahedrons (three sided pyramids).
Agate | Varieties, Uses, Formation | Britannica
Agate, common semiprecious silica mineral, a variety of chalcedony that occurs in bands of varying colour and transparency. Agate is essentially quartz, and its physical properties are in general those of that mineral. See silica mineral (table). Agate is …
Quartz | Properties, Varieties, Occurrence and Uses …
Quartz is a mineral that is composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2.
Jasper | Polished, Red, Banded | Britannica
Jasper, opaque, fine-grained or dense variety of the silica mineral chert that exhibits various colours. Chiefly brick red to brownish red, it owes its colour to admixed hematite; but when it occurs with clay admixed, the colour is a yellowish white or gray, or with goethite a brown or yellow.
Quartz | Definition, Types, Uses, & Facts | Britannica
Quartz is the second most abundant mineral in Earth's crust after feldspar. It occurs in nearly all acid igneous, metamorphic, and sedimentary rocks. It is an essential mineral in such silica-rich felsic rocks as granites, granodiorites, and rhyolites.
Silicon: mining and processing | Britannica
The Tana quarry in Norway, near the North Cape - here quartz is mined. Mineral quartz is 99 percent silicon, one of the most important raw materials of the 21st century. Silicon is in every computer, mobile phone and, of course, in solar cells. ... Be on the lookout for your …
Collection – All Sorts of Quartz | Smithsonian …
Quartz is the major component of beach sand and an important mineral in many types of rocks, including granite. Quartz is composed of the elements silicon and oxygen, and in its pure state is colorless. However, just small amounts of …
mineral
Encyclopædia Britannica, Inc. ... One of the most common minerals, quartz occurs in many areas in a variety of forms. Semiprecious gem stones of quartz include amethyst, tigereye, agate, and onyx. Siliceous sinter, or geyserite, is an impure quartz deposited by hot springs and is a form of opal. The fire opal has an internal iridescence of ...
Igneous rock
Igneous rock - Minerals, Magma, Crystals: The major mineralogical components of igneous rocks can be divided into two groups: felsic (from feldspar and silica) and mafic (from magnesium and ferrous iron). The felsic minerals include quartz, tridymite, cristobalite, feldspars (plagioclase and alkali feldspar), feldspathoids (nepheline and leucite), muscovite, and corundum.
quartz
The two most common chemical elements in the Earth's crust, oxygen and silicon, combine to form the mineral quartz, the second most abundant mineral after feldspar. Quartz has the chemical formula SiO 2. Sometimes minor impurities—such as lithium, sodium, potassium, and titanium—may be present. There are many varieties of quartz.
Chert and flint | Mineral, Sedimentary Rock | Britannica
chert and flint, very fine-grained quartz (q.v.), a silica mineral with minor impurities.Several varieties are included under the general term chert: jasper, chalcedony, agate (qq.v.), flint, porcelanite, and novaculite. Flint is gray to black and nearly opaque (translucent brown in thin splinters) because of included carbonaceous matter. Opaque, dull, whitish to pale-brown or …
Quartz Mineral | Photos, Uses, Properties, Pictures
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Quartz | Common Minerals
Quartz is one of the most common minerals because it is chemically and physically stable at Earth's surface conditions. It is a significant component of hydrothermal veins and felsic igneous rocks, and is often the dominant mineral …
Venus's-hairstone | mineral | Britannica
Venus's-hairstone, variety of quartz interspersed with fine crystals of the mineral rutile
Mineral
Mineral - Polymorphism, Crystalline Structure, Chemical Compounds: Polymorphism is the ability of a specific chemical composition to crystallize in more than one form. This generally occurs as a response to …