Mineralogy Database

Rhomboclase Mineral Data

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General Rhomboclase Information

Help on Chemical  Formula: Chemical Formula: (H5O2)+Fe+++(SO4)2•2(H2O)
Help on Composition: Composition: Molecular Weight = 321.04 gm
   Iron      17.40 %  Fe   24.87 % Fe2O3
   Hydrogen   2.83 %  H    25.25 % H2O
   Sulfur    19.98 %  S    49.88 % SO3
   Oxygen    59.80 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: HFe3+(SO4)2•4(H2O)
Help on Environment: Environment: Secondary mineral formed by alteration of pyrite, especially in an arid climate; typically of post-mining origin.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1891
Help on Locality: Locality: Smolnik (Szomolnok), 16 km northeast of Roznava, Slovakia. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named from the Greek for rhomb, for the typical rhombic crystal outline, and for to break, for its perfect cleavage.
Help on Name Pronunciation: Name Pronunciation: Rhomboclase + Pronunciation Say RHOMBOCLASE
Help on Synonym: Synonym: ICSD 4302
  PDF 27-245

Rhomboclase Image

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Comments: Platy crystal rhomboclase spray.
Location: Rio Tinto, Andalucia, Spain. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Rhomboclase Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.5314:1:0.2964
Help on Cell Dimensions: Cell Dimensions: a = 9.723, b = 18.295, c = 5.424, Z = 4; V = 964.83 Den(Calc)= 2.21
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P nma
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.113(1), 3.331(0.45), 4.05(0.45),
Help on Forms: Forms:

Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

Forms: ( 0 2 1) ( 0 1 0) ( 1 1 0) ( 1 1 1) ( 0 0 1)

Warning: this java applet does not work in some browsers because of security restrictions.


Physical Properties of Rhomboclase

Help on Cleavage: Cleavage: {001} Perfect, {110} Good
Help on Color: Color: Bluish, Colorless, Greenish, Gray, Yellow.
Help on Density: Density: 2.23
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Conchoidal - Uneven - Uneven fracture producing small, conchoidal fragments.
Help on Hardness: Hardness: 2 - Gypsum
Help on Luster: Luster: Vitreous - Pearly
Help on Streak: Streak: white

Optical Properties of Rhomboclase

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.021 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.03 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2602,KPDmeas= 0.2578,KC= 0.2525
Ncalc = 1.56
Help on Optical Data: Optical Data: Biaxial (+), a=1.534, b=1.553, g=1.638, bire=0.1040, 2V(Calc)=54, 2V(Meas)=27.

Calculated Properties of Rhomboclase

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.26 gm/cc
note: Specific Gravity of Rhomboclase =2.23 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0054773418
Boson Index = 0.9945226582
Help on Photoelectric: Photoelectric: PERhomboclase = 6.27 barns/electron
U=PERhomboclase x rElectron Density= 14.21 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Rhomboclase is Not Radioactive

Rhomboclase Classification

Help on  Dana Class: Dana Class: (29)Hydrated Acid and Sulfates
  (29.01)(Hydrated, Acid)
  (29.01.01)Dana Group Rhomboclase (H5O2)Fe(SO4)2•2(H2O) P nma 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 07.CB.55 07 - SULFATES (SELENATES, TELLURATES)
  07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O
  07.CB -With only medium-sized cations
07.CB.55 Rhomboclase (H5O2)Fe(SO4)2•2(H2O) P nma 2/m 2/m 2/m

Other Rhomboclase Information

Help on References: References: NAME( AntBidBlaNic5) 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 Rhomboclase :
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 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 07.CB.55





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