Grossite | |
---|---|
General | |
Category | Oxide minerals |
Formula (repeating unit) | CaAl4O7 |
IMA symbol | Gss [1] |
Strunz classification | 4.CC.15 |
Dana classification | 07.03.02.01 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/c |
Unit cell | a = 12.94, b = 8.91 c = 5.44 [Å]; β = 107.01°; Z = 4 |
Identification | |
Color | Colorless to white |
Crystal habit | Lathlike or subhedral rounded grains in polycrystalline aggregates rimmed by melilite (in meteorites) |
Luster | Vitreous |
Streak | White |
Diaphaneity | Transparent |
Specific gravity | 2.88 |
Optical properties | Biaxial (+) |
Refractive index | nα = 1.618 nβ = 1.618 nγ = 1.652 |
Birefringence | δ = 0.034 |
2V angle | Measured: 15° |
References | [2] [3] [4] |
Grossite is a calcium aluminium oxide mineral with formula CaAl4O7. It is a colorless to white vitreous mineral which crystallizes in the monoclinic crystal system. [3] [4]
Grossite was first described 1994 for an occurrence in the Hatrurim Formation of Israel. It was named for Shulamit Gross (1923–2012) of the Geological Survey of Israel. [2] [4]
It occurs within high temperature metamorphosed impure limestone of the Hatrurim Formation and also within calcium-aluminium rich inclusions in chondritic meteorites. Associated minerals in the Hatrurium include brownmillerite, mayenite and larnite. In meteorites it occurs with perovskite, melilite, hibonite, spinel and calcium rich pyroxene. [2]
Axinite is a brown to violet-brown, or reddish-brown bladed group of minerals composed of calcium aluminium boro-silicate, (Ca,Fe,Mn)3Al2BO3Si4O12OH. Axinite is pyroelectric and piezoelectric.
Anorthite is the calcium endmember of the plagioclase feldspar mineral series. The chemical formula of pure anorthite is CaAl2Si2O8. Anorthite is found in mafic igneous rocks. Anorthite is rare on the Earth but abundant on the Moon.
Augite is a common rock-forming pyroxene mineral with formula (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6. The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees.
Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO
3, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., En80Fs20).
Clintonite is a calcium magnesium aluminium phyllosilicate mineral. It is a member of the margarite group of micas and the subgroup often referred to as the "brittle" micas. Clintonite has the chemical formulaCa(Mg,Al)
3(Al
3Si)O
10(OH)
2. Like other micas and chlorites, clintonite is monoclinic in crystal form and has a perfect basal cleavage parallel to the flat surface of the plates or scales. The Mohs hardness of clintonite is 6.5, and the specific gravity is 3.0 to 3.1. It occurs as variably colored, colorless, green, yellow, red, to reddish-brown masses and radial clusters.
Cummingtonite is a metamorphic amphibole with the chemical composition (Mg,Fe2+
)
2(Mg,Fe2+
)
5Si
8O
22(OH)
2, magnesium iron silicate hydroxide.
Hedenbergite, CaFeSi2O6, is the iron rich end member of the pyroxene group having a monoclinic crystal system. The mineral is extremely rarely found as a pure substance, and usually has to be synthesized in a lab. It was named in 1819 after M.A. Ludwig Hedenberg, who was the first to define hedenbergite as a mineral. Contact metamorphic rocks high in iron are the primary geologic setting for hedenbergite. This mineral is unique because it can be found in chondrites and skarns (calc–silicate metamorphic rocks). Since it is a member of the pyroxene family, there is a great deal of interest in its importance to general geologic processes.
Aegirine is a member of the clinopyroxene group of inosilicate minerals. Aegirine is the sodium endmember of the aegirine-augite series. Aegirine has the chemical formula NaFeSi2O6 in which the iron is present as Fe3+. In the aegirine-augite series the sodium is variably replaced by calcium with iron(II) and magnesium replacing the iron(III) to balance the charge. Aluminium also substitutes for the iron(III). Acmite is a fibrous, green-colored variety.
Brownmillerite is a rare oxide mineral with chemical formula Ca2(Al,Fe)2O5. It is named for Lorrin Thomas Brownmiller (1902–1990), chief chemist of the Alpha Portland Cement Company, Easton, Pennsylvania.
Bentorite is a mineral with the chemical formula Ca6(Cr,Al)2(SO4)3(OH)12·26H2O. It is colored violet to light violet. Its crystals are hexagonal to dihexagonal dipyramidal. It is transparent and has vitreous luster. It has perfect cleavage. It is not radioactive. Bentorite is rated 2 on the Mohs Scale.
Ettringite is a hydrous calcium aluminium sulfate mineral with formula: Ca6Al2(SO4)3(OH)12·26H2O. It is a colorless to yellow mineral crystallizing in the trigonal system. The prismatic crystals are typically colorless, turning white on partial dehydration. It is part of the ettringite-group which includes other sulfates such as thaumasite and bentorite.
Ye'elimite is the naturally occurring form of calcium sulfoaluminate, Ca4(AlO2)6SO4. It gets its name from Har Ye'elim in Israel in the Hatrurim Basin west of the Dead Sea where it was first found in nature by Shulamit Gross.
Portlandite is a hydroxide-bearing mineral typically included in the oxide mineral class. It is the naturally occurring form of calcium hydroxide (Ca(OH)2) and the calcium analogue of brucite (Mg(OH)2).
Chlormayenite (after Mayen, Germany), Ca12Al14O32[☐4Cl2], is a rare calcium aluminium oxide mineral of cubic symmetry.
Krotite is a natural mineral composed of calcium, aluminium and oxygen, with the molecular formula CaAl2O4. It is the low-pressure dimorph of CaAl2O4, of which the high-pressure dimorph is named dmitryivanovite.
Dmitryivanovite is a natural mineral composed of calcium, aluminium and oxygen, with the molecular formula CaAl2O4. It was reported in 2009 in a calcium-aluminium-rich inclusion in the carbonaceous chondrite meteorite 470 (NWA470) CH3, which landed in North Africa. The mineral name was chosen to honor Dmitriy A. Ivanov (1962–1986), a geologist, mineralogist, and petrologist who died on a field expedition.
Merrillite is a calcium phosphate mineral with the chemical formula Ca9NaMg(PO4)7. It is an anhydrous, sodic member of the whitlockite group.
Aradite is a very rare mineral with formula BaCa6[(SiO4)(VO4)](VO4)2F. Aradite and its phosphorus-analogue, zadovite, were found in paralavas (rocks formed due to pyrometamorphism) of the Hatrurim Formation. Both aradite and zadovite have structures similar to that of nabimusaite. Structure of all three minerals is related to that of hatrurite.
Hexacelsian is a rare barium silicate mineral with the formula BaAl2Si2O8. It was discovered in the Hatrurim Basin in Israel, where the Hatrurim Formation of rocks formed due to exposed pyrometamorphism.
Shulamit Gross was an Israeli mineralogist and geologist who studied the Hatrurim Formation.