Mineralogy Database

Pentahydrite Mineral Data

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General Pentahydrite Information

Help on Chemical  Formula: Chemical Formula: MgSO4•5(H2O)
Help on Composition: Composition: Molecular Weight = 210.45 gm
   Magnesium  11.55 %  Mg   19.15 % MgO
   Hydrogen    4.79 %  H    42.80 % H2O
   Sulfur     15.24 %  S    38.05 % SO3
   Oxygen     68.42 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Mg(SO4)•5(H2O)
Help on Environment: Environment: Pseudomorphs of dehydration of epsomite.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1951
Help on Locality: Locality: The Geysers, Sonoma County, California, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named from the Greek, penta, "five" and hydros "water" in allusion to the 5 water molecules in the formula.
Help on Name Pronunciation: Name Pronunciation: Pentahydrite + Pronunciation Say PENTAHYDRITE
Help on Synonym: Synonym: ICSD 2776
  PDF 25-532

Pentahydrite Image

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Comments: White, powdery pentahydrite.
Location: Shaft 371, Schlema-Hartenstein area, Erzgebirge, Saxony, Germany. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Pentahydrite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.6004:1:0.5758
Help on Cell Dimensions: Cell Dimensions: a = 6.335, b = 10.55, c = 6.075, Z = 2; alpha = 99.17°, beta = 109.88°, gamma = 75° V = 364.10 Den(Calc)= 1.92
Help on Crystal System: Crystal System: Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1

Physical Properties of Pentahydrite

Help on Cleavage: Cleavage: None
Help on Color: Color: White, Light blue, Light greenish blue.
Help on Density: Density: 1.9
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Habit: Habit: Efflorescences - Crystals covering matrix, generally produced from transpiro-evaporation.
Help on Habit: Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Help on Hardness: Hardness: 2.5 - Finger Nail
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Pentahydrite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.025 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.025 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2574,KPDmeas= 0.2574,KC= 0.2512
Ncalc = 1.48
Help on Optical Data: Optical Data: Biaxial (-), a=1.482, b=1.492, g=1.493, bire=0.0110, 2V(Calc)=34, 2V(Meas)=45.13.

Calculated Properties of Pentahydrite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=1.99 gm/cc
note: Specific Gravity of Pentahydrite =1.90 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEPentahydrite = 1.29 barns/electron
U=PEPentahydrite x rElectron Density= 2.56 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Pentahydrite is Not Radioactive

Pentahydrite Classification

Help on  Dana Class: Dana Class: (29)Hydrated Acid and Sulfates
  (29.06)where A XO4 � x(H2O)
  (29.06.07)Chalchanthite Group (Triclinic: P-1) Chalcanthite CuSO4•5(H2O) P1 1 Siderotil FeSO4•5(H2O) P1 1 Pentahydrite MgSO4•5(H2O) P1 1 Jokokuite MnSO4•5(H2O) P1 1
Help on  Strunz Class: Strunz Class: 07.CB.20 07 - SULFATES (SELENATES, TELLURATES)
  07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O
  07.CB -With only medium-sized cations
07.CB.20 Chalcanthite CuSO4•5(H2O) P1 1
07.CB.20 Jokokuite MnSO4•5(H2O) P1 1
07.CB.20 Pentahydrite MgSO4•5(H2O) P1 1
07.CB.20 Siderotil FeSO4•5(H2O) P1 1

Other Pentahydrite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Pentahydrite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info

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Dana No: Strunz No: 07.CB.20





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