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(Ca,Na)2(Al,Mg,Fe2+)(Si2O7)
Sorosilicate (Si2O7 groups), melilite group
Crystal system: Tetragonal
Specific gravity: 2.96 measured, 3.00 calculated
Hardness: 4½ to 5
Streak: White
Colour: Light browm
Luminescence: No fluorescence under UV
Environments
Volcanic igneous environments
Carbonatites
Localities
At the type locality, Ol Doinyo Lengai, Ngorongoro District, Arusha region, Tanzania, alumoåkermanite occurs
as tabular phenocrysts up to 1.5 mm in size and microphenocrysts in a fine-grained groundmass. The geological setting
is olivine-free
melilite -
nephelinitic ashes and
tuff produced by a
carbonatite volcano. Associated minerals include
aegirine - augite,
combeite, melanite,
nepheline, sodalite,
spinel, titanite and
wollastonite
(Mindat, HOM).
Alumoåkermanite from Ol Doinyo Lengai -
Image
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