General Information:
Chemical Formula:
Ca2Mn++Al2BO3Si4O12(OH)
Composition:
(Molecular Weight = 628.02 gm)
Calcium 12.76 % Ca
Manganese 8.75 % Mn
Aluminum 8.59 % Al
Silicon 17.89 % Si
Boron 3.44 % B
Hydrogen 0.16 % H
Oxygen 48.40 % O
Empirical Formula:
Ca2Mn2+Al2(BO3)Si4(O)12(OH)
Environment:
Contact metamorphic, hydrothermal, and alpine vein rocks.
Name Origin:
From the Greek acine - "axe" in allusion to the acute shape of typical crystals and the from the Latin magnes = "magnet" in reference to Mn in the chemical formula.
Physical Properties:
Cleavage:
[100] Distinct, [001] Poor, [110] Poor
Color:
brown, colorless, yellowish, pale violet, or reddish.
Density:
3.27 - 3.29, Average = 3.28
Diaphaniety:
Transparent to subtranslucent
Habits:
Massive - Granular - Common texture observed in granite and other igneous rock., Lamellar - Thin laminae producing a lamellar structure.,
Hardness:
6.5-7 - Pyrite-Quartz
Luminescence:
Fluorescent.
Luster:
Vitreous (Glassy)
Streak:
white
More details...