Graeserite Mineral Data

General Graeserite Information

Chemical Formula:

(Fe+++,Ti)4Ti3AsO13(OH)

Composition:

Molecular Weight = 666.95 gm

Titanium 21.54 % Ti 35.93 % TiO₂

Iron 33.49 % Fe 47.89 % Fe₂O₃

Arsenic 11.23 % As 14.83 % As₂O₃

Hydrogen 0.15 % H 1.35 % H₂O

Oxygen 33.58 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺₄Ti₃AsO₁₃(OH)

Environment:

The Fe++ dominant analog of tomichite and the As+++ dominant analog of derbylite. In hydrothermal veins in a two-mica paragneiss.

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

Larchelitini, in the Monte Leone Nappe, Binntal region, western Alps, Switzerland. Link to MinDat.org Location Data.

Name Origin:

For Prof. Dr. Stefan Graeser (1935-), in recognition of his extensive research on the oxides and sulfosalts of arsenic in the Binntal region of Switzerland.

Name Pronunciation:

Graeserite + Pronunciation

Synonym:

ICSD 50374

IMA1996-010

Graeserite Image

Images:

Graeserite

Comments: SEM photomicrograph of an aggregate of hair-like graeserite crystals. CanMin v36:1083.
Location: Monte Leone Nappe, Binntal region, Western Alps, Switzerland. Scale: Scale Bar 1 mm.
© Canadian Mineralogist

Graeserite Crystallography

Axial Ratios:

a:b:c =0.5027:1:0.3503

Cell Dimensions:

a = 7.184, b = 14.289, c = 5.006, Z = 2; beta = 105.17° V = 495.97 Den(Calc)= 4.47

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: A2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.681(1), 2.846(0.8), 1.5825(0.5),

Crystal Structure:

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Berlepsch P , Armbruster T , Schweizerische Mineralogische und Petrographische Mitteilungen , 78 (1998) p.1-9, The crystal structure of Pb2+-bearing graeserite, Pb0.14(Fe,Ti)7AsO12+x(OH)2-x,, a mineral of the derbylite group, Locality: Gorb, Binn valley, Western Alps, Switzerland

Physical Properties of Graeserite

Cleavage:

{100} Distinct

Color:

Black.

Density:

4.62

Diaphaneity:

Opaque

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Hardness:

5.5 - Knife Blade

Luster:

Metallic

Streak:

black

Optical Properties of Graeserite

Optical Data:

NCalc= 2.48 - from Gladstone-Dale relationship (KC = 0.3315) where Ncalc=Dcalc*KC+1
NCalc= 2.53 - from Gladstone-Dale relationship (KC = 0.3315) where Ncalc=Dmeas*KC+1

Calculated Properties of Graeserite

Electron Density:

Bulk Density (Electron Density)=4.24 gm/cc
note: Specific Gravity of Graeserite =4.47 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Graeserite= 21.57 barns/electron
U=PE_Graeserite x rElectron Density= 91.37 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Graeserite is Not Radioactive

Graeserite Classification

Dana Class:

46.02.03.03 (46)Basic or Halogen-Containing Antimonites, Arsenites and Phosphites

(46.02)with miscellaneous formulae

(46.02.03)Derbylite Group

46.02.03.01 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m

46.02.03.02 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 2₁/m 2/m

46.02.03.03 Graeserite! (Fe,Ti)4Ti3AsO13(OH) A2/m 2/m

Strunz Class:

04.JB.55 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.J - Arsenites, Antimonites, Bismuthites, Sulfites,

04.JB -Arsenites, antimonites, bismuthites; with additional anions, without H2O

04.JB.55 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 2₁/m 2/m

04.JB.55 Graeserite! (Fe,Ti)4Ti3AsO13(OH) A2/m 2/m

04.JB.55 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m

Other Graeserite Information

References:

NAME( MinRec) PHYS. PROP.(MinRec)

See Also:

Links to other databases for Graeserite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (UofA)
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info

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

Graeserite

(Fe+++,Ti)4Ti3AsO13(OH)
Dana No: 46.02.03.03 Strunz No: 04.JB.55
Locality:

Notes: