Aenigmatite

Aenigmatite is a sodium, iron, titanium inosilicate mineral with formula: Na2Fe2+5TiSi6O20. It forms brown to black triclinic lamellar crystals. It has Mohs hardness of 5.5 to 6 and specific gravity of 3.74 to 3.85. Aenigmatite forms a solid-solution series with wilkinsonite, Na2Fe2+4Fe3+2Si6O20. Aenigmatite is primarily found in peralkaline volcanic rocks, pegmatites, and granites as well as silica-poor intrusive rocks. It was first described in 1865 for an occurrence in the Ilimaussaq intrusive complex of west Greenland. Its name comes from the Greek word for "riddle". It was also reported from the Kaidun meteorite, possibly a Mars meteorite, landed on March 1980 in South Yemen. Other notable studied occurrences include: Narssarssukand elsewhere in Greenland. In the Khibiny and Lovozero massifs, Kola Peninsula, Russia. From Pantelleria, Italy. In the USA, from Granite Mountain, near Little Rock, Pulaski Co., Arkansas, and Santa Rosa, Sonoma Co., California. In Australia, from Warrumbungle volcano, Nandewar volcano, and the Mt. Warning complex, New South Wales; and the Peak Range Province, Queensland. From Logan Point quarry, Dunedin volcano, New Zealand.
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General Information:
 Chemical Formula:
Na2Fe++5TiSi6O20
 Composition:
(Molecular Weight = 861.60 gm)
Sodium 5.34 % Na
Titanium 5.56 % Ti
Iron 32.41 % Fe
Silicon 19.56 % Si
Oxygen 37.14 % O 
 Empirical Formula:
Na2Fe2+5TiSi6O20
 Environment:
Sodalite-syenite rocks.
 IMA Status:
Approved IMA 1963
 Locality:
TL: Julianehaab district in southern Greenland.
Physical Properties:
 Cleavage:
[???] Perfect
 Color:
brown or black.
 Density:
3.74 - 3.85, Average = 3.79
 Diaphaniety:
Opaque
 Habits:
Lamellar - Thin laminae producing a lamellar structure., ,
 Hardness:
5-6 - Between Apatite and Orthoclase
 Luminescence:
Non-fluorescent.
 Luster:
Subadamantine
 Streak:
reddish brown
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ENIGMATITE