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Bassanite Mineral Data

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General Bassanite Information

Help on Chemical  Formula: Chemical Formula: 2CaSO4•(H2O)
Help on Composition: Composition: Molecular Weight = 290.30 gm
   Calcium   27.61 %  Ca   38.63 % CaO
   Hydrogen   0.69 %  H     6.21 % H2O
   Sulfur    22.09 %  S    55.16 % SO3
   Oxygen    49.60 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: 2(Ca)2(SO4)•(H2O)
Help on Environment: Environment: In cavities in leucite-tephrite blocks, 1906 eruption. Dehydrates at 130 deg. C. Hydrates to gypsum in a humid atmosphere.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1910
Help on Locality: Locality: Vesuvius, Italy. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Francesco Basani (185301916). Italian paleontologist, University of Naples, Italy.
Help on Name Pronunciation: Name Pronunciation: Bassanite + Pronunciation Say BASSANITE
Help on Synonym: Synonym: Hemihydrate
  Plaster of Paris

Bassanite Image

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Comments: White, blocky bassanite crystals on matrix.
Location: Taft, Kern County, California, USA. Scale: Size Not Given.
© Lou Perloff / Photo Atlas of Minerals

Bassanite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.9476:1:0.5461
Help on Cell Dimensions: Cell Dimensions: a = 12.031, b = 12.695, c = 6.934, Z = 6; V = 1,059.05 Den(Calc)= 2.73
Help on Crystal System: Crystal System: Orthorhombic Space Group: Unk
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.006(1), 2.807(0.85), 6(0.7),

Physical Properties of Bassanite

Help on Color: Color: Colorless, Snow white.
Help on Density: Density: 2.7
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Microscopic Crystals - Crystals visible only with microscopes.
Help on Luster: Luster: Earthy (Dull)
Help on Streak: Streak: white

Optical Properties of Bassanite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.038 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.026 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2051,KPDmeas= 0.2074,KC= 0.1999
Ncalc = 1.54 - 1.55
Help on Optical Data: Optical Data: Uniaxial (+), w=1.55, e=1.57, bire=0.0200.

Calculated Properties of Bassanite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.75 gm/cc
note: Specific Gravity of Bassanite =2.73 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0022687697
Boson Index = 0.9977312303
Help on Photoelectric: Photoelectric: PEBassanite = 4.71 barns/electron
U=PEBassanite x rElectron Density= 12.94 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Bassanite is Not Radioactive

Bassanite Classification

Help on  Dana Class: Dana Class: (29)Hydrated Acid and Sulfates
  (29.06)where A XO4 � x(H2O)
  (29.06.01)Dana Group Bassanite 2CaSO4•(H2O) Unk Ortho
Help on  Strunz Class: Strunz Class: 07.CD.45 07 - SULFATES (SELENATES, TELLURATES)
  07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O
  07.CD -With only large cations
07.CD.45 Bassanite 2CaSO4•(H2O) Unk Ortho

Other Bassanite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Bassanite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info

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Dana No: Strunz No: 07.CD.45





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