General Information:
Chemical Formula:
KMg3(Si3Al)O10(F,OH)2
Composition:
(Molecular Weight = 417.26 gm)
Potassium 9.37 % K
Magnesium 17.47 % Mg
Aluminum 6.47 % Al
Silicon 20.19 % Si
Hydrogen 0.48 % H
Oxygen 46.01 % O
Empirical Formula:
KMg3AlSi3O10(OH)2
Environment:
Contact and regional metamorhic limestones and dolomites.
Locality:
St. Lawrence Co., at Edwards, New York, USA.
Name Origin:
From the Greek flogopos - "resembling fire."
Physical Properties:
Cleavage:
[001] Perfect
Color:
brown, gray, green, yellow, or reddish brown.
Density:
2.7 - 2.9, Average = 2.8
Diaphaniety:
Transparent to translucent
Habits:
Micaceous - Platy texture with "flexible" plates., Scaly - Morphology like fish scales., Lamellar - Thin laminae producing a lamellar structure.
Hardness:
2-2.5 - Gypsum-Finger Nail
Luminescence:
None.
Luster:
Vitreous - Pearly
Streak:
white
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