Mineralogy Database

Holtite Mineral Data

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General Holtite Information

Help on Chemical  Formula: Chemical Formula: Al6(Al,Ta)(BO3)[(SiO4,SbO4,AsO4)]3(O,OH)3
Help on Composition: Composition: Molecular Weight = 2,589.58 gm
   Tantalum  10.48 %  Ta   12.80 % Ta2O5
   Aluminum  24.17 %  Al   45.67 % Al2O3
   Iron       0.22 %  Fe    0.28 % FeO
   Silicon   11.50 %  Si   24.59 % SiO2
   Boron      1.59 %  B     5.11 % B2O3
   Antimony   5.64 %  Sb    7.50 % Sb2O5
   Arsenic    2.03 %  As    3.11 % As2O5
   Hydrogen   0.08 %  H     0.73 % H2O
   Oxygen    44.30 %  O
            ______        ______ 
            100.00 %       99.78 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Al23.2Ta1.5Fe2+0.1B3.8Si10.6Sb1.2As0.7O69.6(OH)2.1
Help on Environment: Environment: As coatings on stibiotantalite and replacing tantalite in a pegmatite.
Help on IMA Status: IMA Status: Approved IMA 1971
Help on Locality: Locality: At Bunbury Gully, Greenbushes, Western Australia. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Harold Edward Holt (1908-1967), Prime minister of Australia (1966-1967).
Help on Name Pronunciation: Name Pronunciation: Holtite Say HOLTITE
Help on Synonym: Synonym: ICSD 66143
  PDF 25-1209

Holtite Image

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Comments: Pale violet crystalline granular holtite in pegmatite.
Location: Vasin-Myl'k Mountain, Voron'i Tundry, Kola Peninsula, Murmansk District, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Holtite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.3943:1:1.7134
Help on Cell Dimensions: Cell Dimensions: a = 4.6914, b = 11.896, c = 20.383, Z = 1; V = 1,137.55 Den(Calc)= 3.78
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): 10.28(1), 2.94(0.4), 5.89(0.34),

Physical Properties of Holtite

Help on Cleavage: Cleavage: {001} Distinct
Help on Color: Color: Beige white, Brown, Greenish, Greenish brown, Light brown white.
Help on Density: Density: 3.6 - 3.9, Average = 3.75
Help on Diaphaneity: Diaphaneity: Semitransparent
Help on Habit: Habit: Blocky - Crystal shape tends to be equant (e.g. feldspars).
Help on Habit: Habit: Pseudo Hexagonal - Crystals show a hexagonal outline.
Help on Hardness: Hardness: 8.5 - Chrysoberyl
Help on Luminescence: Luminescence: Fluorescent, Short UV=bright yellow, Long UV=dull orange.
Help on Luster: Luster: Vitreous - Resinous
Help on Streak: Streak: white

Optical Properties of Holtite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1953,KPDmeas= 0.1968,KC= 0.1955
Ncalc = 1.7 - 1.76
Help on Optical Data: Optical Data: Biaxial (-), a=1.705-1.746, b=1.728-1.759, g=1.73-1.761, bire=0.0150-0.0250, 2V(Calc)=32-42, 2V(Meas)=20-55. Dispersion r < v.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
Help on Pleochroism (z): Pleochroism (z): yellow.

Calculated Properties of Holtite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.62 gm/cc
note: Specific Gravity of Holtite =3.78 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0087965282
Boson Index = 0.9912034718
Help on Photoelectric: Photoelectric: PEHoltite = 132.55 barns/electron
U=PEHoltite x rElectron Density= 480.27 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Holtite is Not Radioactive

Holtite Classification

Help on  Dana Class: Dana Class: (54)Nesosilicate Borosilicates and Some Beryllosilicates
  (54.01)with (BO3)
  (54.01.03)Dana Group Holtite Al6(Al,Ta)(BO3)[(SiO4,SbO4,AsO4)]3(O,OH)3 P nma 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.AJ.10 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AJ -Nesosilicates with BO3 triangles and/or B[4], Be[4] tetrahedra,
09.AJ.10 Dumortierite Al6.5-7(BO3)(SiO4)3(O,OH)3 Pcmn 2/m 2/m 2/m
09.AJ.10 Holtite Al6(Al,Ta)(BO3)[(SiO4,SbO4,AsO4)]3(O,OH)3 P nma 2/m 2/m 2/m
09.AJ.10 Magnesiodumortierite (Mg,Ti,[])<1(Al,Mg)2Al4Si3O18-y(OH)yBy=2-3 Pmcn 2/m 2/m 2/m

Other Holtite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic2)
Help on See Also: See Also: Links to other databases for Holtite :
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: 09.AJ.10





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