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Crystal Habit
In mineralogy, crystal habit is the characteristic external shape of an individual crystal or aggregate of crystals. The habit of a crystal is dependent on its crystallographic form and growth conditions, which generally creates irregularities due to limited space in the Crystallization, crystallizing medium (commonly in Rock (geology), rocks).Klein, Cornelis, 2007, ''Minerals and Rocks: Exercises in Crystal and Mineral Chemistry, Crystallography, X-ray Powder Diffraction, Mineral and Rock Identification, and Ore Mineralogy,'' Wiley, third edition, Wenk, Hans-Rudolph and Andrei Bulakh, 2004, ''Minerals: Their Constitution and Origin,'' Cambridge, first edition, Crystal forms Recognizing the habit can aid in mineral identification and description, as the crystal habit is an external representation of the Crystal structure, internal ordered atomic arrangement. Most natural crystals, however, do not display ideal habits and are commonly malformed. Hence, it is also important to des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corundum
Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. Corundum has two primary gem varieties: ruby and sapphire. Rubies are red due to the presence of chromium, and sapphires exhibit a range of colors depending on what transition metal is present. A rare type of sapphire, padparadscha sapphire, is pink-orange. The name "corundum" is derived from the Tamil- Dravidian word ''kurundam'' (ruby-sapphire) (appearing in Sanskrit as ''kuruvinda''). Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost all other minerals. It is commonly used as an abrasive on sandpaper and on large tools used in machining metals, plastics, and wood. Emery, a variety of corundum with no value a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver
Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc Refining (metallurgy), refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes bimetallism, alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yuanfuliite
Yuanfuliite is a black submetal mineral. The mineral is named after the geologist Yuan Fuli. It can be found in places like Russia, Sakha Republic, and Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of .... It occurs in metamorphosed magnesium marble.http://www.handbookofmineralogy.org/pdfs/yuanfuliite.pdf References External links Mindat.org: Yuanfuliite Borates {{mineral-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scolecite
Scolecite is a tectosilicate mineral belonging to the zeolite group; it is a hydrated calcium silicate, Ca Al2 Si3 O10· 3H2O. Only minor amounts of sodium and traces of potassium substitute for calcium. There is an absence of barium, strontium, iron and magnesium.Zeolites of the World (1992) Scolecite is isostructural (having the same structure) with the sodium-calcium zeolite mesolite and the sodium zeolite natrolite, but it does not form a continuous chemical series with either of them. It was described in 1813, and named from the Greek word, σκώληξ (sko-lecks) = "worm" because of its reaction to the blowpipe flame. Crystal class It is monoclinic m with space group Cc, but crystals are pseudotetragonal. Scolecite, like natrolite and mesolite, usually occurs as acicular (needle-like) and fibrous aggregations. It has nearly the same angles between the crystal faces as does natrolite, but natrolite is orthorhombic and scolecite is monoclinic. The etched figures (figu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natrolite
Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula . The type locality is Hohentwiel, Hegau, Germany. It was named natrolite by Martin Heinrich Klaproth in 1803. The name is derived from ''natron'' (), the Greek word for soda, in reference to the sodium content, and ''lithos'' (), meaning stone. Needle stone or needle-zeolite are other informal names, alluding to the common acicular habit of the crystals, which are often very slender and are aggregated in divergent tufts. The crystals are frequently epitaxial overgrowths of natrolite, mesolite, and gonnardite in various orders. Properties Larger crystals most commonly have the form of a square prism terminated by a low pyramid, the prism angle being nearly a right angle. The crystals are tetragonal in appearance, though actually orthorhombic. There are perfect cleavages parallel to the faces of the prism. The mineral also often occurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scolecite
Scolecite is a tectosilicate mineral belonging to the zeolite group; it is a hydrated calcium silicate, Ca Al2 Si3 O10· 3H2O. Only minor amounts of sodium and traces of potassium substitute for calcium. There is an absence of barium, strontium, iron and magnesium.Zeolites of the World (1992) Scolecite is isostructural (having the same structure) with the sodium-calcium zeolite mesolite and the sodium zeolite natrolite, but it does not form a continuous chemical series with either of them. It was described in 1813, and named from the Greek word, σκώληξ (sko-lecks) = "worm" because of its reaction to the blowpipe flame. Crystal class It is monoclinic m with space group Cc, but crystals are pseudotetragonal. Scolecite, like natrolite and mesolite, usually occurs as acicular (needle-like) and fibrous aggregations. It has nearly the same angles between the crystal faces as does natrolite, but natrolite is orthorhombic and scolecite is monoclinic. The etched figures (figu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natrolite
Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula . The type locality is Hohentwiel, Hegau, Germany. It was named natrolite by Martin Heinrich Klaproth in 1803. The name is derived from ''natron'' (), the Greek word for soda, in reference to the sodium content, and ''lithos'' (), meaning stone. Needle stone or needle-zeolite are other informal names, alluding to the common acicular habit of the crystals, which are often very slender and are aggregated in divergent tufts. The crystals are frequently epitaxial overgrowths of natrolite, mesolite, and gonnardite in various orders. Properties Larger crystals most commonly have the form of a square prism terminated by a low pyramid, the prism angle being nearly a right angle. The crystals are tetragonal in appearance, though actually orthorhombic. There are perfect cleavages parallel to the faces of the prism. The mineral also often occurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acicular (crystal Habit)
__NOTOC__ Acicular, in mineralogy, refers to a crystal habit composed of slender, needle-like crystals. Crystals with this habit tend to be fragile. Complete, undamaged acicular specimens are uncommon. The term "acicular" derives from the Late Latin "acicula" meaning "little needle". Strictly speaking, the word refers to a growth habit that is slender and tapering to a point. Prismatic crystals are not acicular; however, colloquial usage has altered the commonly understood meaning of the word. When writing for mineralogical publications, authors should restrict their usage of "acicular" to crystals with the tapering growth habit. To add to the confusion, some minerals are described with various morphological terms. For example, natrolite is often described as slender prismatic and millerite is often described as filiform or capillary. Examples Minerals with an acicular habit include mesolite, natrolite, malachite, gypsum, rutile, brochantite and bultfonteinite. Crystals of dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocidolite
Riebeckite is a sodium-rich member of the amphibole group of silicate minerals, chemical formula Na2(Fe2+3Fe3+2)Si8O22(OH)2. It forms a solid solution series with magnesioriebeckite. It crystallizes in the monoclinic system, usually as long prismatic crystals showing a diamond-shaped cross section, but also in fibrous, bladed, acicular, columnar, and radiating forms. Its Mohs hardness is 5.0–6.0, and its specific gravity is 3.0–3.4. Cleavage is perfect, two directions in the shape of a diamond; fracture is uneven, splintery. It is often translucent to nearly opaque. Name and discovery Riebeckite was first described in 1888 for an occurrence on Socotra Island, Aden Governorate, Yemen, and named for German explorer Emil Riebeck (1853–1885). The mineral is also known as crocidolite. Occurrence Riebeckite typically forms dark-blue elongated to fibrous crystals in highly alkali granites, syenites, rarely in felsic volcanics, granite pegmatites and schist. It occurs in banded i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. Quartz is the mineral defining the val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as a synthetic product. Notable examples include fused quartz, fumed silica, silica gel, opal and aerogels. It is used in structural materials, microelectronics (as an Insulator (electricity), electrical insulator), and as components in the food and pharmaceutical industries. Structure In the majority of silicates, the silicon atom shows tetrahedral coordination geometry, tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. In contrast, CO2 is a linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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