General Information:
Chemical Formula:
NaFe++3Al6(BO3)3Si6O18(OH)4
Composition:
(Molecular Weight = 1,044.39 gm)
Aluminum 15.50 % Al
Iron 16.04 % Fe
Silicon 16.14 % Si
Boron 3.11 % B
Hydrogen 0.39 % H
Nitrogen 1.34 % N
Oxygen 47.49 % O
Empirical Formula:
NFe3+3Al6BO33Si6O18(OH)4
Environment:
Granites, diorites, gabbro pegmatites, greisens, skarns and quartz veins.
Locality:
Sonnenberg, Bodenmais and Spessart, Germany.
Name Origin:
Old name of unknown origin.
Physical Properties:
Cleavage:
[1011] Indistinct
Color:
black, brownish black, greenish black, or bluish black.
Density:
3.1 - 3.2, Average = 3.15
Diaphaniety:
Opaque
Habits:
Acicular - Occurs as needle-like crystals., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Striated - Parallel lines on crystal surface or cleavage face.
Hardness:
7.5 - Garnet
Luminescence:
Piezoelectric.
Luster:
Vitreous (Glassy)
Streak:
brown
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