Alloclasite Mineral Data
General Alloclasite Information
Chemical Formula:
(Co,Fe)AsS
Composition:
Molecular Weight = 165.15 gm
Iron 8.45 % Fe
Cobalt 26.76 % Co
Arsenic 45.37 % As
Sulfur 19.42 % S
______
100.00 %
Empirical Formula:
Co0.75 Fe2+ 0.25 AsS
Environment:
In calcite or quartz veins of apparently low temperature, late stage hydrothermal origin. Also in silicified, recrystallized metamorphic rock.
IMA Status:
Valid Species (Pre-IMA) 1866
Locality:
In the Elizabeth mine, Oravita (Oravicza), Romania. From the Silverfields mine, Cobalt, and the Siscoe mine, Miller Lake, Gowganda, Ontario, Canada. Link to MinDat.org Location Data.
Name Origin:
From the Greek for "other", and "to break," because its cleavage was believed to be different from marcasite, which it resembles.
Name Pronunciation:
Alloclasite + Pronunciation
Synonym:
ICSD 36395
PDF 25-246
Alloclasite Crystallography
Axial Ratios:
a:b:c =0.8316:1:0.6091
Cell Dimensions:
a = 4.662, b = 5.606, c = 3.415, Z = 2; V = 89.25 Den(Calc)= 6.14
Crystal System:
Orthorhombic - Disphenoidal H-M Symbol (2 2 2) Space Group: P 22121
X Ray Diffraction:
By Intensity(I/Io ): 2.75(1), 2.47(0.9), 1.82(0.7),
Physical Properties of Alloclasite
Cleavage:
{101} Perfect, {010} Distinct
Color:
Steel gray.
Density:
6.17
Diaphaneity:
Opaque
Fracture:
Brittle - Uneven - Very brittle fracture producing uneven fragments.
Habit:
Aggregates - Made of numerous individual crystals or clusters.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Habit:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Hardness:
5 - Apatite
Luster:
Metallic
Streak:
black
Optical Properties of Alloclasite
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Alloclasite in Air
λ
R1
R 2
∑ R1 (λ)
∑ R2 (λ)
400 nm
47.20
49.20
420 nm
47.50
49.60
440 nm
47.80
50.00
460 nm
48.20
50.40
480 nm
48.70
50.90
500 nm
49.10
51.30
520 nm
49.40
51.50
540 nm
49.30
51.50
560 nm
49.10
51.30
580 nm
48.70
51.00
600 nm
48.10
50.60
620 nm
47.60
50.10
640 nm
47.20
49.80
660 nm
46.90
49.50
680 nm
46.70
49.20
700 nm
46.60
49.00
Calculated Relative Intensity Colors of Alloclasite in Air
Relative Intensity
0%
20%
40%
60%
80%
100%
120%
140%
160%
180%
190%
R1
R2
Calculated Properties of Alloclasite
Electron Density:
Bulk Density (Electron Density)=5.63 gm/cc note: Specific Gravity of Alloclasite =6.14 gm/cc.
Fermion Index:
Fermion Index = 0.0032484804 Boson Index = 0.9967515196
Photoelectric:
PEAlloclasite = 45.20 barns/electronU=PEAlloclasite x r Electron Density= 254.61 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Alloclasite is Not Radioactive
Alloclasite Classification
Dana Class:
02.12.06.02 (02) Sulfides - Including Selenides and Tellurides
(02.12) where Am Bn Xp, with (m+n):p=1:2
(02.12.06) Dana Group
02.12.06.01 Glaucodot (Co,Fe)AsS C mmm 2/m 2/m 2/m
02.12.06.02 Alloclasite (Co,Fe)AsS P 22121 2 2 2
Strunz Class:
02.EB.10b 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
02.E - Metal Sulfides, M:S � 1:2
02.EB -M:S = 1:2, with Fe, Co, Ni, PGE, etc.
02.EB.10b Alloclasite (Co,Fe)AsS P 22121 2 2 2
Other Alloclasite Information
References:
NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
See Also:
Links to other databases for Alloclasite :
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
15 - WWW-MINCRYST
Search for Alloclasite using:
[AOL ]
[Bing ]
[Dog Pile ]
[GeoScienceWorld ]
[HotBot ]
[Ixquick ]
[Lycos ]
[MAMMA ]
[Scirus ]
[Teoma ]
[WebCrawler ]
[Wikipedia ]
[YAHOO ]
Visit our Advertisers for Alloclasite :
Ask about Alloclasite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in
Español
Print or Cut-and-Paste your Alloclasite Specimen Label here :
Alloclasite
(Co,Fe)AsS
Dana No: 02.12.06.02 Strunz No: 02.EB.10b
Locality:
Notes:
Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.