General Information:
Chemical Formula:(K,Na)3(Fe++,Mn)7Ti2Si8O24(O,OH)7
Composition:(Molecular Weight = 1,312.74 gm)Potassium 6.70 %
K Sodium 1.31 %
NaTitanium 7.29 %
TiManganese 7.32 %
MnIron 22.33 %
FeSilicon 17.12 %
SiHydrogen 0.13 %
H Oxygen 37.78 %
O Empirical Formula: K2.25Na0.75Fe2+5.25Mn2+1.75Ti2Si8O29.25OH1.75
Environment:Mineral in zircon-bearing syenites.
Locality:Langesundfiord, near Brevik, Norway.
Name Origin:From the Greek aster - "star" and fyllon - "leaf."
Physical Properties: Cleavage:[001] Perfect
Color:brown, brownish red, bronze yellow, or gold yellow.
Density:3.3 - 3.4, Average = 3.34
Diaphaniety:Translucent to Opaque
Habits:Bladed - Aggregates of thin lath-like crystals (e.g. kyanite)., Stellate - Occurs as spherical, radial aggregates radiating from a "star" like point., Crystalline - Fine - Occurs as w ell-formed fine sized crystals.
Hardness:3-3.5 - Calcite-Copper Penny
Luminescence:None.
Luster:Adamantine - Pearly
Streak:yellowish brown
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