| Goethite | |
|---|---|
 Goethite,from Minas Gerais, Brazil
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| General | |
| Category | Mineral |
| Chemical formula | α-FeO(OH) |
| Identification | |
| Color | Yellowish to reddish to dark brown |
| Crystal system | Orthorhombic 2/m2/m2/m |
| Cleavage | Perfect 010 |
| Fracture | uneven to splintery |
| Mohs Scale hardness | 5 - 5. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the In Chemistry, hydroxide is the most common name for the diatomic Anion OH− consisting of Oxygen and Hydrogen A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions In Crystallography, the orthorhombic Crystal system is one of the seven Lattice Point groups Orthorhombic lattices result from stretching Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types In the field of Mineralogy, fracture is a term used to describe the shape and texture of the surface formed when a Mineral is broken The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material 5 |
| Luster | adamantine to dull |
| Refractive index | Opaque to sub-translucent |
| Streak | brown, brownish yellow to orange yellow |
| Specific gravity | 3. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium The streak (also called powder color) of a Mineral is the Color of the powder produced when it is dragged across an unweathered surface Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 3 - 4. 3 |
| Fusibility | Fusible at 5 - 5. Fusibility is the ease with which a material will Melt. Materials such as solder require a low melting point so that when heat is applied to a joint the solder will melt before 5 |
| Other Characteristics | Becomes magnetic in reducing flame |
| References | [1][2][3][4] |
Goethite, named after the German polymath Johann Wolfgang von Goethe, is an iron bearing oxide mineral found in soil and other low temperature environments. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. A polymath ( Greek polymathēs, πολυμαθής "having learned much" is a person whose knowledge is not restricted to one subject area ˈjoːhan ˈvɔlfgaŋ fɔn ˈgøːtə (in English generally ˈgɝːtə 28 August 1749 22 March 1832 was a German writer Goethite has been well known since prehistoric times for its use as a pigment. For the drug referred to as "pigment" see Black tar heroin. Evidence has been found of its use in paint pigment samples taken from the caves of Lascaux in France. Lascaux is the setting of a complex of Caves in southwestern France famous for its prehistoric Cave paintings The original caves are located near This article is about the country For a topic outline on this subject see List of basic France topics. It was first described in 1806 for occurrences in the Mesabi iron ore district of Minnesota. The Mesabi Iron Range is a vast deposit of Iron ore and the largest of four major iron ranges in the region collectively known as the Iron Range of Minnesota Minnesota ( Native Americans demonstrated the name to early settlers Recently, nanoparticulate authigenic goethite was shown to be the most common diagenetic iron oxyhydroxide in both marine and lake sediments. An authigenic mineral or Sedimentary rock deposit is one that was generated where it is found or observed In Geology and Oceanography, diagenesis is any chemical physical or biological change undergone by a Sediment after its initial deposition and during [5]
Contents |
Composition
It is an iron oxyhydroxide. A number of species are dubbed iron(III oxide-hydroxide. These chemicals are Oxide - Hydroxides of Iron, and may occur in Anhydrous (( or Goethite's hardness ranges from 5. 0 to 5. 5 on the Mohs Scale, and its specific gravity varies from 3. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 3 to 4. 3. The mineral forms prismatic needle-like crystals, but is more typically massive. In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating
Feroxyhyte and Lepidocrocite are both polymorphs of the iron oxyhydroxide FeO(OH). Feroxyhyte is an oxide/hydroxide of iron, δ-FeO(OH It occurs in Manganese - Iron nodules on the Pacific Ocean floor Lepidocrocite (γ-FeO(OH also called esmeraldite or hydrohematite, is an iron oxide-hydroxide Mineral. Although they have the same chemical formula as goethite they each have different crystalline structures making them distinct minerals.
Usage
Its main modern use is as an iron ore, being referred to as brown iron ore. Iron ores are rocks and Minerals from which Metallic Iron can be economically extracted It does have some use as a clay earth pigment. Clay earth pigments are naturally occurring Minerals that have been used since prehistoric times as Pigments The primary types are Ochre Iron rich lateritic soils developed over serpentinite rocks in tropical climates are mined for their iron content as well as other metals. Laterite (from the Latin word "later" meaning brick or tile is a surface formation in hot and wet tropical areas which is enriched in Iron and Aluminium Serpentinite is a rock composed of one or more Serpentine Minerals Minerals in this group are formed by serpentinization a hydration and metamorphic
Formation
Goethite often forms through the weathering of other iron-rich minerals, and thus is a common component of soils. Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere. Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel It may also be precipitated by groundwater or in other sedimentary conditions, or form as a primary mineral in hydrothermal deposits. Groundwater is Water located beneath the Ground surface in Soil pore spaces and in the Fractures of lithologic formations Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat
Prevalence
Goethite is found all over the planet, usually in the form of concretions, stalactitic formations, oolites (a form consisting of tiny round grains cemented together), reniform (kidney shapes) or botryoidal (globular, like bunches of grapes) accumulations. A concretion is a volume of Sedimentary rock in which a Mineral cement fills the porosity (i A stalactite ( Greek stalaktites, (Σταλακτίτης from the word for "drip" and meaning "that which drips" is a type of Speleothem Oolite ( egg stone) is a Sedimentary rock formed from Ooids spherical grains composed of concentric layers It is frequently encountered in the swampy areas at the head of spring waters ('bog iron'), on cave floors, and on the bottom of lakes and small creeks. Bog iron refers to impure Iron deposits that develop in bogs or Swamps by the Chemical or Biochemical Oxidation of iron carried The boxworks or gossan resulting from the oxidation of sulfide ore deposites is formed of goethite along with other iron oxides and quartz. Gossan is intensely Oxidized, weathered or decomposed rock usually the upper and exposed part of an Ore deposit or mineral vein Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state
Significant deposits of goethite are found in England, Australia, Cuba, and Michigan, Minnesota, Missouri, Colorado, Alabama, Georgia, Virginia, and Tennessee in the United States. England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland For a topic outline on this subject see List of basic Australia topics. The Republic of Cuba (ˈkjuːbə or) consists of the island of Cuba (the largest and second-most populous island of the Greater Antilles) Isla de la Michigan ( is a Midwestern state of the United States of America. Minnesota ( Native Americans demonstrated the name to early settlers Missouri ( or) is a state in the Midwestern region of the United States bordered by Iowa, Illinois, Kentucky, Tennessee The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. Alabama (formally the State of Alabama;) is a State located in the southern region of the United States of America. The State of Georgia ( is a state in the United States and was one of the original Thirteen Colonies that revolted against British rule The Commonwealth of Virginia ( is an American state Tennessee ( is a state located in the Southern United States. The United States of America —commonly referred to as the
Deposits significant in location, if not in abundance, have been found in Gusev by NASA's Spirit rover, providing strong evidence for the presence of liquid water on the planet Mars in an earlier stage of its development. Gusev Crater is a crater on the planet Mars and is located at 175 MER-A ( Mars Exploration Rover - A) known as Spirit, is the first of the two rovers of NASA 's Mars Exploration Rover
References
- ^ Hurlbut, Cornelius S. ; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed. , Wiley, ISBN 0-471-80580-7
- ^ http://webmineral.com/data/Goethite.shtml Webmineral data
- ^ http://www.mindat.org/min-1719.html Mindat data with locations
- ^ http://www.galleries.com/minerals/oxides/goethite/goethite.htm Mineral galleries
- ^ C. van der Zee, D. Roberts, D. G. Rancourt, C. P. Slomp. Nanogoethite is the dominant reactive oxyhydroxide phase in lake and marine sediments. Geology 31 (2003) 993-996.