General Information:
Chemical Formula:
(Ca,Na)3(Ti,Al)Si2O7(F,OH)2
Composition:
(Molecular Weight = 363.79 gm)
Sodium 1.58 % Na
Calcium 30.30 % Ca
Titanium 9.87 % Ti
Aluminum 1.85 % Al
Silicon 15.44 % Si
Hydrogen 0.14 % H
Oxygen 32.99 % O
Fluorine 7.83 % F
Empirical Formula:
Ca2.75Na0.25Ti0.75Al0.25Si2O7F1.5(OH)0.5
Environment:
Alkalic igneous rocks.
IMA Status:
Approved IMA 1960
Locality:
Nyiragongo crater, Mount Shaheru, Kivu Province, Zaire.
Name Origin:
Named for Gustav Adolf Von Gotzen (1866-1910), German traveler and first European to climb Mt. Shaheru, North Kivu, Zaire.
Physical Properties:
Cleavage:
[100] Perfect, [001] Good
Color:
colorless, very pale yellow, tan, or white.
Density:
3.138 - 3.2, Average = 3.16
Diaphaniety:
Transparent
Habits:
Tabular - Form dimensions are thin in one direction., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Acicular - Occurs as needle-like crystals.
Hardness:
5.5-6 - Knife Blade-Orthoclase
Luster:
Vitreous - Greasy
Streak:
white
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