Stichtite Mineral Data

General Stichtite Information

Chemical Formula:

Mg6Cr2(CO3)(OH)16•4(H2O)

Composition:

Molecular Weight = 654.01 gm

Magnesium 22.30 % Mg 36.98 % MgO

Chromium 15.90 % Cr 23.24 % Cr₂O₃

Hydrogen 3.70 % H 33.06 % H₂O

Carbon 1.84 % C 6.73 % CO₂

Oxygen 56.27 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₆Cr₂(OH)₁₆(CO₃)•4(H₂O)

Environment:

Alteration product of serpentine.

IMA Status:

Valid Species (Pre-IMA) 1910

Locality:

Dundas, Tasmania. Link to MinDat.org Location Data.

Name Origin:

Named after Robert Sticht, director of a mining corporation.

Name Pronunciation:

Stichtite + Pronunciation

Stichtite Image

Images:

Stichtite

Comments: Massive, fibrous, lavender-purple stichtite.
Location: Kaapsche Hoop, Barberton District, Mpumalanga Province, South Africa. Scale: 5x3x2 cm.
© John Betts - Fine Minerals

Stichtite Crystallography

Axial Ratios:

a:c = 1:7.50485

Cell Dimensions:

a = 6.18, c = 46.38, Z = 3; V = 1,534.05 Den(Calc)= 2.12

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: R 3m

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

By Intensity(I/I_o): 7.8(1), 3.91(0.9), 2.6(0.4),

Physical Properties of Stichtite

Cleavage:

{0001} Perfect

Color:

Lilac, Light violet, Pink.

Density:

2.2

Diaphaneity:

Transparent to translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Micaceous - Platy texture with "flexible" plates.

Habit:

Nodular - Tuberose forms having irregular protuberances over the surface.

Hardness:

1.5-2 - Talc-Gypsum

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Magnetism:

Nonmagnetic

Streak:

pale violet blue

Optical Properties of Stichtite

Dichroism (e):

colorless.

Dichroism (w):

colorless.

Gladstone-Dale:

CI meas= 0.103 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.069 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2495,KPDmeas= 0.2405,KC= 0.2679
Ncalc = 1.57 - 1.59

Optical Data:

Uniaxial (+), w=1.516, e=1.542, bire=0.0260.

Calculated Properties of Stichtite

Electron Density:

Bulk Density (Electron Density)=2.17 gm/cc
note: Specific Gravity of Stichtite =2.12 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Stichtite= 4.01 barns/electron
U=PE_Stichtite x rElectron Density= 8.67 barns/cc.

Radioactivity:

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

Stichtite Classification

Dana Class:

16b.06.02.02 (16b)Carbonates - Hydroxyl or Halogen

(16b.06)Dana Type

(16b.06.02)Sjorgrenite-Hydrotalcite Group (Hydrotalcite Subgroup:Rhombohedral)

16b.06.02.01 Hydrotalcite Mg6Al2(CO3)(OH)16•4(H2O) R 3m 3 2/m

16b.06.02.02 Stichtite Mg6Cr2(CO3)(OH)16•4(H2O) R 3m 3 2/m

16b.06.02.03 Pyroaurite Mg6Fe2(CO3)(OH)16•4(H2O) R 3m 3 2/m

16b.06.02.04 Desautelsite Mg6Mn2(CO3)(OH)16•4(H2O) R 3m or R 3m Trig

16b.06.02.05 Droninoite! Ni3FeCl(OH)8•2H2O R 3m, R 3m or R 32 Trig

Strunz Class:

05.DA.50 05 - CARBONATES (NITRATES)

05.D - Carbonates with Additional Anions, with H2O

05.DA -With medium-sized cations

05.DA.50 Desautelsite Mg6Mn2(CO3)(OH)16•4(H2O) R 3m or R 3m Trig

05.DA.50 Comblainite Ni6Co2(CO3)(OH)16•4(H2O) R 3m 3 2/m

05.DA.50 Hydrotalcite Mg6Al2(CO3)(OH)16•4(H2O) R 3m 3 2/m

05.DA.50 Pyroaurite Mg6Fe2(CO3)(OH)16•4(H2O) R 3m 3 2/m

05.DA.50 Reevesite Ni6Fe2(CO3)(OH)16•4(H2O) R 3m 3 2/m

05.DA.50 Stichtite Mg6Cr2(CO3)(OH)16•4(H2O) R 3m 3 2/m

05.DA.50 Takovite Ni6Al2(OH)16(CO3,OH)•4(H2O) R 3m 3 2/m

Other Stichtite Information

References:

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

See Also:

Links to other databases for Stichtite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info

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Ask about Stichtite here :
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Print or Cut-and-Paste your Stichtite Specimen Label here :

Stichtite

Mg6Cr2(CO3)(OH)16•4(H2O)
Dana No: 16b.06.02.02 Strunz No: 05.DA.50
Locality:

Notes: