Grossite
{{Infobox mineral
| name = Grossite
| image =Grossite.png
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| caption =
| category = Oxide minerals
| formula = CaAl4O7
| molweight =
| strunz = 4.CC.15
| dana = 07.03.02.01
| system = Monoclinic
| class = Prismatic (2/m)
(same H-M symbol)
| symmetry = C2/c
| unit cell = a = 12.94, b = 8.91
c = 5.44 [Å]; β = 107.01°; Z = 4
| color = Colorless to white
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| habit = Lathlike or subhedral rounded grains in polycrystalline aggregates rimmed by melilite (in meteorites)
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| luster = Vitreous
| streak = White
| diaphaneity = Transparent
| gravity = 2.88
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| opticalprop = Biaxial (+)
| refractive = nα = 1.618 nβ = 1.618 nγ = 1.652
| birefringence = δ = 0.034
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| 2V = Measured: 15°
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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.[http://www.mindat.org/min-1754.html Mindat.org][http://webmineral.com/data/Grossite.shtml Webmineral data]
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.[http://rruff.geo.arizona.edu/doclib/hom/grossite.pdf Handbook of Mineralogy]
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.