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					 Axial Ratios: a:b:c =0.5816:1:2.1774
 Cell Dimensions: a = 5.118, b = 8.799,
  c = 19.159, Z = 4;
 Crystal Data: Monoclinic. Point Group: 2/m:
  Rarely forms distinct thin tabular crystals, with
  pseudohexagonal outline; commonly foliated
  micaceous aggregates, with lamellae to 3 cm;
  massive.
Mineral Group: Mica group.
Chemical Formula: CaAl2(Al2Si2)O10(OH)2
Composition: Molecular Weight = 398.18 gm
 Calcium 10.07 % Ca 14.08 % CaO
 Aluminum 27.10 % Al 51.21 % Al2O3
 Silicon 14.11 % Si 30.18 % SiO2
 Hydrogen 0.51 % H 4.52 % H2O
 Oxygen 48.22 % O
               = 100.00 % = TOTAL OXIDE
Empirical Formula: CaAl4Si2O10(OH)2
Environment: Commonly associated with corundum as
  an alteration product.
Color: White, Gray, Pinkish gray, Yellowish gray.
Luminescence: Fluorescent, Short UV=sky blue, Long
 UV=strong sky blue. Pearly
Streak: white
Transparent: Translucent.
Luster: Pearly on cleavage, vitreous on lateral faces.
Cleavage: {001} Good
Density: 2.99 - 3.08, Average = 3.03
Diaphaneity: Translucent to subtranslucent
Fracture: Brittle - Generally displayed by glasses and
  most non-metallic minerals.
Tenacity: Laminae brittle.
Habit: Lamellar - Thin laminae producing a lamellar
  structure.
Habit: Massive - Lamellar - Distinctly foliated fine-
  grained forms.
Habit: Scaly - Morphology like fish scales.
Hardness: 3.5-4.5, average=4 , Fluorite
 Occurrence: From low- to medium-grade
 metamorphic rocks, as in emery deposits, chlorite
 and mica schists, and glaucophane-bearing rocks.
 (1) Dana, E.S. (1892) Dana's system of
  mineralogy, (6th edition), 636{637.
 (2) Deer, W.A., R.A. Howie, and J. Zussman
  (1963) Rock-forming minerals, v.
Axial Ratios: a:b:c =0.5771:1:1.1046
Forms: ( 1 1 2) ( 2 2 1) ( 0 1 0) ( 0 0 1)
Crystal Data: Monoclinic. Point Group: 2=m:
  Uncommon in good crystals, tabular or short
  prismatic, with pseudohexagonal outline, to3
  m. Typically irregular foliated or bent
  masses; in scaly aggregates or disseminated
  grains.
Mineral Group: Mica group.
Chemical Formula: K(Mg,Fe++)3[AlSi3O10(OH,F)2
Composition: Molecular Weight = 433.53 gm
Potassium 9.02 % K 10.86 % K2O Magnesium 14.02 % Mg23.24 %
   MgO
Aluminum 6.22 % Al 11.76 % Al2O3 Iron 6.44 % Fe 8.29 % Fe
  O
Silicon 19.44 %Si 41.58 % SiO2 Hydrogen 0.41 % H 3.64 % H2
  O
Oxygen 43.36 % O Fluorine 1.10 % F 1.10 % F
                    100.00 % = TOTAL OXIDE
Empirical Formula: KMg2.5Fe2+0.5AlSi3O10(OH)1.75F0.25
Environment: Granitic rocks. Forms a series with phlogopite. Has
  several polytypes (1M, 3T, 2M1). Biotite is now a group name for
  phlogopite, siderophyllite and eastonite.
 Color: Dark brown, Greenish brown, Blackish
 brown, Yellow, White.
 Luminescence: Non-fluorescent.
 Luster: Vitreous – Pearly
 Streak: gray
 Cleavage: {001} Perfect
 Density: 2.8 - 3.4, Average = 3.09
 Diaphaneity: Transparent to translucent to
  opaque
 Fracture: Uneven - Flat surfaces (not cleavage)
  fractured in an uneven pattern.
 Habit: Lamellar - Thin laminae producing a
  lamellar structure.
 Habit: Micaceous - Platy texture with "flexible"
  plates.
 Habit: Pseudo Hexagonal - Crystals show a
  hexagonal outline.
 Hardness: 2.5-3 - Finger Nail-Calcite
 Animportant rock-forming mineral under a wide
 range of conditions. In regionally metamorphosed
 schists and gneisses, and in contact
 metamorphosed rocks; in granites to nepheline
 syenites; less common in extrusive igneous rocks,
 from rhyolites to basalts. Characteristic of potassic
 hydrothermal alteration; in detrital sediments.
 (1) Dana, E.S. (1892) Dana's system of
  mineralogy, (6th edition), 627{632.
 (2) Deer, W.A., R.A. Howie, and J. Zussman
  (1963) Rock-forming minerals, v. 3, sheet silicates,
  55{84.
Axial Ratios: a:b:c =0.5808:1:2.2474
Forms: ( 1 1 2) ( 2 2 1) ( 0 1 0) ( 0 0 1)
Crystal Data: Monoclinic. Point Group: 2=m or m
 (1M). Tabular to prismatic pseudohexagonal
 crystals, commonly with rounded terminal faces,
 to 20 cm. In coarse to fine scaly aggregates and
 massive.
Mineral Group: Mica group.
Chemical Formula: K(Li,Al)3(Si,Al)4O10(F,OH)2
Composition: Molecular Weight = 388.30 gm
Potassium 10.07 % K 12.13 % K2O
Lithium 3.58 % Li 7.70 % Li2O
Aluminum 6.95 % Al 13.13 % Al2O3
Silicon 28.93 % Si 61.89 % SiO2
Hydrogen 0.26 % H 2.32 % H2O
Oxygen 45.32 % O
Fluorine 4.89 % F 4.89 % F -2.06 % -O=F2
              100.00 % = TOTAL OXIDE
Empirical Formula: KLi2AlSi4O10F(OH)
Environment: Lithia-bearing pegmatites.
 Cleavage:  {001} Perfect
 Color: Colorless, Gray white, Lilac,
  Yellowish, White.
 Density: 2.8 - 2.9, Average = 2.84
 Diaphaneity: Translucent
 Fracture: Uneven - Flat surfaces (not
  cleavage) fractured in an uneven pattern.
 Habit:   Foliated - Two dimensional platy
  forms.
 Habit: Massive - Uniformly indistinguishable
  crystals forming large masses.
 Habit: Platy - Sheet forms (e.g. micas).
 Hardness: 2.5-3 - Finger Nail-Calcite
 Luminescence: Non-fluorescent.
 Luster: Vitreous – Pearly
 Streak: white

				
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posted:12/11/2010
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