Mooihoekite

Last updated
Mooihoekite
General
Category Sulfide mineral
Formula
(repeating unit)
Cu9Fe9S16
IMA symbol Mho [1]
Strunz classification 2.CB.10b
Crystal system Tetragonal
Crystal class Scalenohedral (42m)
H-M symbol: (4 2m)
Space group P42m
Unit cell a = 10.58 Å, c = 5.38 Å;
Volume = 602.22 Å3; Z = 1
Identification
Formula mass 1,587.59 g/mol
ColorPale yellow. Tarnishes to pinkish brown and purple
Crystal habit Granular - Generally occurs as anhedral to subhedral crystals in matrix
Mohs scale hardness4
Luster Metallic
Streak Black
Diaphaneity Opaque
Specific gravity 4.36
Optical propertiesWeakly anisotropic
References [2] [3] [4] [5] [6] [7]

Mooihoekite is a copper iron sulfide mineral with chemical formula of Cu9Fe9S16. The mineral was discovered in 1972 and received its name from its discovery area, the Mooihoek mine in Transvaal, South Africa. [5]

Contents

Crystal structure and optical properties

Mooihoekite crystallizes in the tetragonal crystal system. It has a short optical c-axis that is perpendicular to two longer a-axes of equal length. For Mooihoekite, the c-axis is a 4-fold rotoinversion axis. [3]

Mooihoekite is an opaque mineral which shows weak anisotropism in polished section under reflected light microscopy. It goes slightly extinct every 90°. [3]

Occurrence

It is found in massive sulfide from pipe-shaped dunite pegmatite in the norite zone of the Bushveld igneous complex in South Africa. It has also been found in troctolite from the basal Duluth gabbro in Minnesota, US; in the Talnakh area, Norilsk region, western Siberia; at Krzemianka, Poland; in the Malanjkhand copper-molybdenum deposit, Madhya Pradesh, India; and the Stillwater igneous complex in Montana, US. [6] [7]

Mooihoekite occurs in association with haycockite, magnetite, troilite, cuprian pentlandite, mackinawite, sphalerite, and moncheite in the Mooihoek mine and with haycockite, native copper, troilite, pentlandite, cubanite and magnetite in the Duluth complex. [7]

Uses

Mooihoekite is a rare mineral that is mostly used for research purposes. It has similar properties to chalcopyrite CuFeS2, making it helpful in the study of ore deposits and the study of the central portion of the Cu-Fe-S phase system. [3] Mooihoekite, chalcopyrite, talnakhite, and haycockite all play key roles in the study of ore genesis and beneficiation.

Related Research Articles

<span class="mw-page-title-main">Pentlandite</span> Iron–nickel sulfide

Pentlandite is an iron–nickel sulfide with the chemical formula (Fe,Ni)9S8. Pentlandite has a narrow variation range in nickel to iron ratios (Ni:Fe), but it is usually described as 1:1. In some cases, this ratio is skewed by the presence of pyrrhotite inclusions. It also contains minor cobalt, usually at low levels as a fraction of weight.

<span class="mw-page-title-main">Chalcopyrite</span> Copper iron sulfide mineral

Chalcopyrite ( 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.

<span class="mw-page-title-main">Bornite</span> Sulfide mineral

Bornite, also known as peacock ore, is a sulfide mineral with chemical composition Cu5FeS4 that crystallizes in the orthorhombic system (pseudo-cubic).

<span class="mw-page-title-main">Skarn</span> Hard, coarse-grained, hydrothermally altered metamorphic rocks

Skarns or tactites are coarse-grained metamorphic rocks that form by replacement of carbonate-bearing rocks during regional or contact metamorphism and metasomatism. Skarns may form by metamorphic recrystallization of impure carbonate protoliths, bimetasomatic reaction of different lithologies, and infiltration metasomatism by magmatic-hydrothermal fluids. Skarns tend to be rich in calcium-magnesium-iron-manganese-aluminium silicate minerals, which are also referred to as calc-silicate minerals. These minerals form as a result of alteration which occurs when hydrothermal fluids interact with a protolith of either igneous or sedimentary origin. In many cases, skarns are associated with the intrusion of a granitic pluton found in and around faults or shear zones that commonly intrude into a carbonate layer composed of either dolomite or limestone. Skarns can form by regional or contact metamorphism and therefore form in relatively high temperature environments. The hydrothermal fluids associated with the metasomatic processes can originate from a variety of sources; magmatic, metamorphic, meteoric, marine, or even a mix of these. The resulting skarn may consist of a variety of different minerals which are highly dependent on both the original composition of the hydrothermal fluid and the original composition of the protolith.

<span class="mw-page-title-main">Nickeline</span> Nickel arsenide mineral

Nickeline or niccolite is a mineral consisting primarily of nickel arsenide (NiAs). The naturally-occurring mineral contains roughly 43.9% nickel and 56.1% arsenic by mass, but composition of the mineral may vary slightly.

<span class="mw-page-title-main">Pyrrhotite</span> Magnetic iron sulfide mineral

Pyrrhotite is an iron sulfide mineral with the formula Fe(1-x)S. It is a nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is weakly magnetic. The magnetism decreases as the iron content decreases, and troilite is non-magnetic. Pyrrhotite is generally tabular and brassy/bronze in color with a metallic luster. The mineral occurs with mafic igneous rocks like norites, and may form from pyrite during metamorphic processes. Pyrrhotite is associated and mined with other sulfide minerals like pentlandite, pyrite, chalcopyrite, and magnetite, and has been found globally.

<span class="mw-page-title-main">Cobaltite</span> Sulfide mineral composed of cobalt, arsenic, and sulfur

Cobaltite is a sulfide mineral composed of cobalt, arsenic, and sulfur, CoAsS. Its impurities may contain up to 10% iron and variable amounts of nickel. Structurally, it resembles pyrite (FeS2) with one of the sulfur atoms replaced by an arsenic atom.

<span class="mw-page-title-main">Sperrylite</span>

Sperrylite is a platinum arsenide mineral with the chemical formula PtAs2 and is an opaque metallic tin white mineral which crystallizes in the isometric system with the pyrite group structure. It forms cubic, octahedral or pyritohedral crystals in addition to massive and reniform habits. It has a Mohs hardness of 6 - 7 and a very high specific gravity of 10.6.

<span class="mw-page-title-main">Fukuchilite</span>

Fukuchilite, Cu
3
FeS
8
, is a copper iron sulfide named after the Japanese mineralogist Nobuyo Fukuchi (1877–1934), that occurs in ore bodies of gypsum-anhydrite at the intersection points of small masses of barite, covellite, gypsum and pyrite, and is mostly found in the Hanawa mine in the Akita prefecture of Honshū, Japan where it was first discovered in 1969. It occurs in masses within the third geologic unit of the Kuroko type deposits within the mine.

<span class="mw-page-title-main">Troilite</span> Rare iron sulfide mineral: FeS

Troilite is a rare iron sulfide mineral with the simple formula of FeS. It is the iron-rich endmember of the pyrrhotite group. Pyrrhotite has the formula Fe(1-x)S which is iron deficient. As troilite lacks the iron deficiency which gives pyrrhotite its characteristic magnetism, troilite is non-magnetic.

<span class="mw-page-title-main">Bushveld Igneous Complex</span> Large early layered igneous intrusion

The Bushveld Igneous Complex (BIC) is the largest layered igneous intrusion within the Earth's crust. It has been tilted and eroded forming the outcrops around what appears to be the edge of a great geological basin: the Transvaal Basin. It is approximately 2 billion years old and is divided into four different limbs: the northern, southern, eastern, and western limbs. The Bushveld Complex comprises the Rustenburg Layered suite, the Lebowa Granites and the Rooiberg Felsics, that are overlain by the Karoo sediments. The site was first publicised around 1897 by Gustaaf Molengraaff who found the native South African tribes residing in and around the area.

<span class="mw-page-title-main">Layered intrusion</span>

A layered intrusion is a large sill-like body of igneous rock which exhibits vertical layering or differences in composition and texture. These intrusions can be many kilometres in area covering from around 100 km2 (39 sq mi) to over 50,000 km2 (19,000 sq mi) and several hundred metres to over one kilometre (3,300 ft) in thickness. While most layered intrusions are Archean to Proterozoic in age, they may be any age such as the Cenozoic Skaergaard intrusion of east Greenland or the Rum layered intrusion in Scotland. Although most are ultramafic to mafic in composition, the Ilimaussaq intrusive complex of Greenland is an alkalic intrusion.

<span class="mw-page-title-main">Cumulate rock</span> Igneous rocks formed by the accumulation of crystals from a magma either by settling or floating.

Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Cumulate rocks are named according to their texture; cumulate texture is diagnostic of the conditions of formation of this group of igneous rocks. Cumulates can be deposited on top of other older cumulates of different composition and colour, typically giving the cumulate rock a layered or banded appearance.

Violarite (Fe2+Ni23+S4) is a supergene sulfide mineral associated with the weathering and oxidation of primary pentlandite nickel sulfide ore minerals.

<span class="mw-page-title-main">Creighton Mine</span> Underground mine in Canada

Creighton Mine is an underground nickel, copper, and platinum-group elements (PGE) mine. It is presently owned and operated by Vale Limited in the city of Greater Sudbury, Ontario, Canada. Open pit mining began in 1901, and underground mining began in 1906. The mine is situated in the Sudbury Igneous Complex (SIC) in its South Range geologic unit. The mine is the source of many excavation-related seismic events, such as earthquakes and rock burst events. It is home to SNOLAB, and is currently the deepest nickel mine in Canada. Expansion projects to deepen the Creighton Mine are currently underway.

<span class="mw-page-title-main">Cubanite</span> Copper iron sulfide mineral

Cubanite is a copper iron sulfide mineral that commonly occurs as a minor alteration mineral in magmatic sulfide deposits. It has the chemical formula CuFe2S3 and when found, it has a bronze to brass-yellow appearance. On the Mohs hardness scale, cubanite falls between 3.5 and 4 and has a orthorhombic crystal system. Cubanite is chemically similar to chalcopyrite, however it is the less common copper iron sulfide mineral due to crystallization requirements.

Iron oxide copper gold ore deposits (IOCG) are important and highly valuable concentrations of copper, gold and uranium ores hosted within iron oxide dominant gangue assemblages which share a common genetic origin.

<span class="mw-page-title-main">Geerite</span> Copper sulfide mineral

Geerite is a copper sulfide mineral with the chemical formula Cu8S5. The mineral is named after the original collector, Adam Geer, of Utica, New York, US.

Skaergaardite is an intermetallic platinum group mineral with the general chemical formula PdCu. The mineral is named after its discovery location: the Skaergaard intrusion, Kangerdlugssuaq area, East Greenland. The mineral name was approved by the International Mineralogical Association in 2003. The mineral has also been reported in the Duluth intrusion in Minnesota and the Rum layered intrusion in Scotland.

<span class="mw-page-title-main">Djerfisherite</span>

Djerfisherite is an alkali copper–iron sulfide mineral and a member of the djerfisherite group.

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. Mineralienatlas
  3. 1 2 3 4 Cabri, L.J. and Hall, S.R. (1972) Mooihoekite and Haycockite, Two New Copper-Iron Sulfides, and Their Relationship to Chalcopyrite and Talnakhite. American Mineralogist, 57, 689-708.
  4. Hall, S.R. and Rowland, J.F. (1973) The Crystal Structure of Synthetic Mooihoekite. Acta Crystallographica, 29, 2365-2372.
  5. 1 2 Webmineral data
  6. 1 2 Mindat.org
  7. 1 2 3 Handbook of Mineralogy