Marcasite
Marcasite
General
Category	Mineral species
Chemical formula	FeS2
Identification
Molecular Weight	119. 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 The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one 98 gm/cm3
Color	Brass Yellow
Crystal system	Orthorhombic
Cleavage	[010] Indistinct
Fracture	Irregular/Uneven
Tenacity	Brittle
Mohs Scale hardness	6-6. A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions 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	Metallic
Ultraviolet fluorescence	None
Streak	Dark-grey to black. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. Fluorescence is a Luminescence that is mostly found as an The streak (also called powder color) of a Mineral is the Color of the powder produced when it is dragged across an unweathered surface
Density	4. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 875 g/cm3

The mineral marcasite, sometimes called white iron pyrite, is iron sulfide (FeS₂). A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation Marcasite is often mistakenly confused with pyrite, but marcasite is lighter and more brittle. Specimens of marcasite often crumble and break up due to the unstable crystal structure, and it is this crystal structure that is the main difference between marcasite and pyrite. In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. Though marcasite has the same chemical formula as pyrite, it crystallizes in a different crystal system, thereby making it a separate mineral. 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 In jewelry, pyrite used as a gem is improperly termed "marcasite". A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash True marcasite is never used as a gem, due to its brittle and chemically unstable structure.

Two halves of a ball of radiating marcasite from France.

Marcasite can be formed as both a primary or a secondary mineral.

As a primary mineral it forms nodules, concretions and crystals in a variety of sedimentary rock, such as at Dover, Kent, England, where it forms as sharp individual crystals and crystal groups, and nodules (similar to those shown here) in chalk. Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock) Dover is a town and major ferry port in the county of Kent, England. KENT (1400 AM) is a Radio station broadcasting a Adult Standards/MOR format 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 Chalk (ʧɔːk is a soft white porous Sedimentary rock, a form of Limestone composed of the Mineral Calcite. It can also be found in low-temperature hydrothermal veins. Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat

As a secondary mineral it forms by chemical alteration of a primary mineral such as pyrrhotite or chalcopyrite. Pyrrhotite is an unusual Iron Sulfide mineral with a variable iron content Fe(1-xS (x = 0 to 0 Chalcopyrite (ˌkælkoʊˈpaɪraɪt kal-co-pie-right —"kal" as in " cal endar" "co" as in co de is a Copper On fresh surfaces it is pale yellow to almost white and has a bright metallic luster. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. It tarnishes to a yellowish or brownish color and gives a black streak. It is a brittle material that cannot be scratched with a knife. The thin, flat, tabular crystals, when joined in groups, are called "cockscombs. "

Marcasite may go through a condition known as "pyrite decay", in which a specimen slowly disintegrates into a white powder. Little is known about this detrimental condition. It only affects certain marcasite specimens seemingly at random, while other specimens remain unaffected. When a specimen goes through pyrite decay, the marcasite reacts with moisture in the air, the sulfur combining with water to produce sulfuric acid that attacks other sulfide minerals and mineral labels. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. It is most important to remove an afflicted specimen from other minerals to prevent this "disease" from spreading.

Some research has suggested bacteria may aid and accelerate this process by literally 'eating' the marcasite. What is known is that samples with a rough surface tend to decay faster than those with bright, shiny faces, probably due to the greater surface area to react with water in the air, and also it's clear that samples kept in a dry environment (low humidity) are less likely to decay. Humidity is the amount of water vapor in the air In daily language the term "humidity" is normally taken to mean Relative humidity.

Other minerals often found associated with marcasite are pyrite, galena, sphalerite, fluorite and calcite. Galena is the natural mineral form of Lead sulfide. It is the most important Lead Ore mineral Sphalerite (( Zn, Fe) S) is a Mineral that is the chief Ore of Zinc. Fluorite (also called fluorspar) is a Mineral composed of Calcium fluoride, Ca[[Fluorine F2]] Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3

See also

• List of minerals

External links

• How Minerals Form and Change "Pyrite oxidation under room conditions". This is a List of Minerals for which there are Wikipedia articles