Erythrite Mineral Data

General Erythrite Information

Chemical Formula:

Co3(AsO4)2•8(H2O)

Composition:

Molecular Weight = 598.76 gm

Cobalt 29.53 % Co 41.55 % Co₂O₃

Arsenic 25.03 % As 38.39 % As₂O₅

Hydrogen 2.69 % H 24.07 % H₂O

Oxygen 42.75 % O

______ ______

100.00 % 104.01 % = TOTAL OXIDE

Empirical Formula:

Co₃(AsO₄)₂•8(H₂O)

Environment:

Secondary mineral in cobalt-bearing deposits

IMA Status:

Valid Species (Pre-IMA) 1832

Locality:

Grube Daniel, Schneeberg, Germany. Link to MinDat.org Location Data.

Name Origin:

Named from the Greek, erythros for "red."

Name Pronunciation:

Erythrite + Pronunciation

Synonym:

Cobalt Bloom

ICSD 81385

PDF 33-413

Erythrite Image

Images:

Cobaltkoritnigite Erythrite

Comments: Dark purplish cobaltkoritnigite with pink erythrite.
Location: Schneeberg District, Erzgebirge, Saxony, Germany. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Erythrite Skutterudite

Comments: Erythrite crystal on massive skutterudite.
Location: Bou Azzer, Morocco. Scale: Crystal size 1.5 cm.
© John Veevaert

Erythrite Crystallography

Axial Ratios:

a:b:c =0.7629:1:0.3545

Cell Dimensions:

a = 10.2, b = 13.37, c = 4.74, Z = 2; beta = 105.016° V = 624.34 Den(Calc)= 3.18

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: I2/m

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

By Intensity(I/I_o): 6.72(1), 3.003(0.47), 3.227(0.42),

Forms:

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

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Physical Properties of Erythrite

Cleavage:

{010} Perfect

Color:

Colorless, Violet red, Light pink, Purple red.

Density:

3.06 - 3.18, Average = 3.12

Diaphaneity:

Transparent to subtranslucent

Fracture:

Sectile - Curved shavings or scrapings produced by a knife blade, (e.g. graphite).

Habit:

Divergent - Crystals radiate from a center without producing stellar forms.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Striated - Parallel lines on crystal surface or cleavage face.

Hardness:

1.5-2 - Talc-Gypsum

Luminescence:

Non-fluorescent.

Luster:

Pearly

Streak:

pinkish red

Optical Properties of Erythrite

Gladstone-Dale:

CI meas= 0.243 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.257 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2086,KPDmeas= 0.2126,KC= 0.2807
Ncalc = 1.86 - 1.89

Optical Data:

Biaxial (+), a=1.626-1.629, b=1.662-1.663, g=1.699-1.701, bire=0.0720-0.0730, 2V(Calc)=88-90, 2V(Meas)=85-90. Dispersion none.

Pleochroism (x):

pale pink.

Pleochroism (y):

pale violet.

Pleochroism (z):

red.

Calculated Properties of Erythrite

Electron Density:

Bulk Density (Electron Density)=3.03 gm/cc
note: Specific Gravity of Erythrite =3.12 gm/cc.

Fermion Index:

Fermion Index = 0.0002092565
Boson Index = 0.9997907435

Photoelectric:

PE_Erythrite= 26.70 barns/electron
U=PE_Erythrite x rElectron Density= 80.96 barns/cc.

Radioactivity:

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

Erythrite Classification

Dana Class:

40.03.06.03 (40)Hydrated Phosphates, etc

(40.03)where (A++)3 (XO4)2 ï¿½ x(H2O)

(40.03.06)Vivianite Group

40.03.06.01 Vivianite Fe3(PO4)2•8(H2O) C 2/m 2/m

40.03.06.02 Baricite (Mg,Fe)3(PO4)2•8(H2O) C 2/m 2/m

40.03.06.03 Erythrite Co3(AsO4)2•8(H2O) I2/m 2/m

40.03.06.04 Annabergite Ni3(AsO4)2•8(H2O) I2/m 2/m

40.03.06.05 Kottigite Zn3(AsO4)2•8(H2O) C 2/m 2/m

40.03.06.06 Parasymplesite Fe3(AsO4)2•8(H2O) C 2/m 2/m

40.03.06.07 Hornesite Mg3(AsO4)2•8(H2O) I2/m 2/m

40.03.06.08 Arupite (Ni,Fe)3(PO4)2•8(H2O) I2/m 2/m

40.03.06.09 Pakhomovskyite! Co3(PO4)2•8(H2O) C 2/m 2/m

Strunz Class:

08.CE.40 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CE -With only medium-sized cations, RO4:H2O ï¿½ 1:2.5

08.CE.40 Arupite (Ni,Fe)3(PO4)2•8(H2O) I2/m 2/m

08.CE.40 Annabergite Ni3(AsO4)2•8(H2O) I2/m 2/m

08.CE.40 Baricite (Mg,Fe)3(PO4)2•8(H2O) C 2/m 2/m

08.CE.40 Erythrite Co3(AsO4)2•8(H2O) I2/m 2/m

08.CE.40 Ferrisymplesite Fe3(AsO4)2(OH)3•5(H2O) None

08.CE.40 Hornesite Mg3(AsO4)2•8(H2O) I2/m 2/m

08.CE.40 Kottigite Zn3(AsO4)2•8(H2O) C 2/m 2/m

08.CE.40 Manganohornesite (Mn,Mg)3(AsO4)2•8(H2O) P 2₁/c 2/m

08.CE.40 Parasymplesite Fe3(AsO4)2•8(H2O) C 2/m 2/m

08.CE.40 Vivianite Fe3(PO4)2•8(H2O) C 2/m 2/m

08.CE.40 Pakhomovskyite! Co3(PO4)2•8(H2O) C 2/m 2/m

Other Erythrite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

Links to other databases for Erythrite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Amethyst Galleries' Mineral Gallery
5 - Athena
6 - Franklin Minerals(Dunn)
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - Scandinavian mineral gallery
18 - WWW-MINCRYST
19 - YupRocks

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

Erythrite

Co3(AsO4)2•8(H2O)
Dana No: 40.03.06.03 Strunz No: 08.CE.40
Locality:

Notes:

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