Mineralogy Database

Topaz Mineral Data

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General Topaz Information

Help on Chemical  Formula: Chemical Formula: Al2SiO4(F,OH)2
Help on Composition: Composition: Molecular Weight = 182.25 gm
   Aluminum  29.61 %  Al   55.95 % Al2O3
   Silicon   15.41 %  Si   32.97 % SiO2
   Hydrogen   0.50 %  H     4.45 % H2O
   Oxygen    43.02 %  O
   Fluorine  11.47 %  F    11.47 % F
               -   %   F    -4.83 % -O=F2    
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Al2(SiO4)F1.1(OH)0.9
Help on Environment: Environment: Pegmatites and high temperature quartz veins. Cavities in granites and rhyolites. Deposited by fluorine-rich vapors in rocks of rhyolite composition.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) Prehistoric
Help on Locality: Locality: Topasos Island in the Red Sea. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after its locality.
Help on Name Pronunciation: Name Pronunciation: Topaz Say TOPAZ
Help on Synonym: Synonym: Pycnite - yellowish white-
 

Topaz Image

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  Topaz

Comments: Transparent sharp gem topaz crystal set upon a matrix of crystallized white albite and silvery muscovite.
Location: Yunu Village, Shigar, Gilgit division, Pakistan. Scale: 1.6 x 1.8 x 4.2 cm.
© Dan Weinrich

Topaz Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.4943:1:0.9545
Help on Cell Dimensions: Cell Dimensions: a = 4.35, b = 8.8, c = 8.4, Z = 4; V = 321.55 Den(Calc)= 3.76
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pbnm
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.937(1), 3.195(0.65), 3.369(0.6),
Help on Forms: Forms:

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

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

Help on Above

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

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Physical Properties of Topaz

Help on Cleavage: Cleavage: {001} Perfect
Help on Color: Color: Colorless, Pale blue, Yellow, Yellowish brown, Red.
Help on Density: Density: 3.5 - 3.6, Average = 3.55
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Brittle - Uneven - Very brittle fracture producing uneven fragments.
Help on Habit: Habit: Crystalline - Coarse - Occurs as well-formed coarse sized crystals.
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 8 - Topaz
Help on Luminescence: Luminescence: Fluorescent, Short UV=golden yellow, Long UV=cream.
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white
 

Optical Properties of Topaz

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.146 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.193 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1653,KPDmeas= 0.1751,KC= 0.2049
Ncalc = 1.72 - 1.77
Help on Optical Data: Optical Data: Biaxial (+), a=1.606-1.629, b=1.609-1.631, g=1.616-1.638, bire=0.0090-0.0100, 2V(Calc)=58-68, 2V(Meas)=48-68. Dispersion noticeable, r > v.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
 

Calculated Properties of Topaz

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.51 gm/cc
note: Specific Gravity of Topaz =3.55 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0074038512
Boson Index = 0.9925961488
Help on Photoelectric: Photoelectric: PETopaz = 1.53 barns/electron
U=PETopaz x rElectron Density= 5.36 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Topaz is Not Radioactive
 

Topaz Classification

Help on  Dana Class: Dana Class: 52.03.01.01 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O
  (52.03)with cations in [6] coordination only
  (52.03.01)Topaz Group
 
52.03.01.01 Topaz Al2SiO4(F,OH)2 Pbnm 2/m 2/m 2/m
 
52.03.01.02 Krieselite! (Al,Ga)2(Ge,C)O4(OH)2 P nma 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.AF.35 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AF -Nesosilicates with additional anions;
 
09.AF.35 Topaz Al2SiO4(F,OH)2 Pbnm 2/m 2/m 2/m
 
09.AF.35 Krieselite! (Al,Ga)2(Ge,C)O4(OH)2 P nma 2/m 2/m 2/m
 

Other Topaz Information

Help on See Also: See Also: Links to other databases for Topaz :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - CalTech Mineral Spectroscopy
5 - GeoScienceWorld
6 - Glendale Community College
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - HyperPhysics
12 - MinDAT
13 - Mineral and Gemstone Kingdom
14 - Mineralienatlas (Deutsch)
15 - Online Mineral Museum
16 - Philatelic Mineralogy
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - Tradeshop.com - The Rainbow of Gems
20 - University of Colorado - Mineral Structure Data
21 - University of Texas at Austin
22 - theimage

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Print or Cut-and-Paste your Topaz Specimen Label here :

Topaz

Al2SiO4(F,OH)2
Dana No: 52.03.01.01 Strunz No: 09.AF.35
Locality:

 

Notes:

 

 


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