Stichtite
A valid IMA mineral species - grandfathered
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About Stichtite
Robert Carl Sticht
Formula:
Mg6Cr3+2(OH)16[CO3] · 4H2O
Colour:
Rose-pink to purple
Lustre:
Waxy, Greasy, Pearly
Hardness:
1½ - 2
Specific Gravity:
2.16
Crystal System:
Trigonal
Member of:
Name:
Named after Robert Carl Sticht (8 October 1856, Hoboken, Hudson County, New Jersey, USA - 30 April 1922, Launceston, Tasmania, Australia), formerly General Manager of the Mount Lyell Mining and Railway Company, Queenstown (Tasmania).
Hydrotalcite Group.
Stichtite has two polytypes, Stichtite-3R and Stichtite-2H (previously known as barbertonite).
See also the related, visually similar woodallite.
Visit gemdat.org for gemological information about Stichtite.
Stichtite has two polytypes, Stichtite-3R and Stichtite-2H (previously known as barbertonite).
See also the related, visually similar woodallite.
Visit gemdat.org for gemological information about Stichtite.Unique Identifiers
Mindat ID:
3784
Long-form identifier:
mindat:1:1:3784:2
IMA Classification of Stichtite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Mg6Cr3+2(OH)16(CO3)·4H2O
First published:
1910
Classification of Stichtite
5.DA.50
5 : CARBONATES (NITRATES)
D : Carbonates with additional anions, with H2O
A : With medium-sized cations
5 : CARBONATES (NITRATES)
D : Carbonates with additional anions, with H2O
A : With medium-sized cations
16b.6.2.2
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
6 : AmBn(XO3)pZqxH2O & with (m+n):p = 8:1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
6 : AmBn(XO3)pZq
11.11.1
11 : Carbonates
11 : Carbonates of Cr and U
11 : Carbonates
11 : Carbonates of Cr and U
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Stt | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Stt | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261–264 doi:10.1180/clm.2020.30 |
Physical Properties of Stichtite
Waxy, Greasy, Pearly
Transparency:
Transparent
Colour:
Rose-pink to purple
Streak:
White to light lilac
Hardness:
1½ - 2 on Mohs scale
Tenacity:
Flexible
Cleavage:
Perfect
{0001}
{0001}
Density:
2.16 g/cm3 (Measured) 2.11 g/cm3 (Calculated)
Optical Data of Stichtite
Type:
Uniaxial (+)
RI values:
nω = 1.516 nε = 1.542
Max. Birefringence:
δ = 0.026
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Low (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Weak
Comments:
O = dark rose-pink to lilac
E = light rose-pink to lilac
E = light rose-pink to lilac
Chemistry of Stichtite
Mindat Formula:
Mg6Cr3+2(OH)16[CO3] · 4H2O
Element Weights:
Common Impurities:
Al,Fe
Crystallography of Stichtite
Polytype:
Formula:
Crystal System:
Class (H-M)
Space Group:
Space Group Setting:
Cell Parameters:
Ratio:
Unit Cell Volume (calc):
Z:
Comment:
| Stichtite-2H | Stichtite-3R |
|---|---|
| Mg6(Cr,Al)2(CO3)(OH)16 · 4H2O | Mg6Cr3+2(OH)16[CO3] · 4H2O |
| Hexagonal | Trigonal |
| 6/mmm(6/m2/m2/m) - Dihexagonal Dipyramidal | 3m(32/m) - Hexagonal Scalenohedral |
| P63/mmc | R3m |
| R3m | |
| a = 6.09689(6) Å, c = 15.6193(8) Å | a = 3.09573(3) Å, c = 23.5069(6) Å |
| a:c = 1 : 2.562 | a:c = 1 : 7.593 |
| V 502.82 ų (Calculated from Unit Cell) | V 195.099 ų |
| Data of cotype specimen (from Mills et al., 2011); Z = 1/4. |
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.8 Å | (100) |
| 3.91 Å | (90) |
| 2.60 Å | (40) |
| 2.32 Å | (30) |
| 1.97 Å | (30) |
| 1.54 Å | (20) |
| 1.51 Å | (20) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 13 : Hadean serpentinization |
Geological Setting:
Highly altered serpentinites and chromitites.
Type Occurrence of Stichtite
General Appearance of Type Material:
Irregularly-shaped masses veins and blebs in serpentine.
Place of Conservation of Type Material:
National School of Mines, Paris, France.
Geological Setting of Type Material:
Serpentinites
Associated Minerals at Type Locality:
Synonyms of Stichtite
Other Language Names for Stichtite
Varieties of Stichtite
| Bouazzerite (of Cailleres) | A local mining term used to describe a ferroan stichtite. |
Relationship of Stichtite to other Species
Member of:
Other Members of Hydrotalcite Group:
| Desautelsite | Mg6Mn3+2(OH)16[CO3] · 4H2O | Trig. 3m(32/m) |
| Droninoite | Ni6Fe3+2(OH)16Cl2 · 4H2O | Trig. 3m(32/m) : R3m |
| Hydrotalcite | Mg6Al2(CO3)(OH)16 · 4H2O | Trig. 3m(32/m) : R3m |
| Iowaite | Mg6Fe3+2(OH)16Cl2 · 4H2O | Trig. 3m(32/m) : R3m |
| Kaznakhtite | Ni6Co3+2(CO3)(OH)16 · 4H2O | Trig. 3 : R3 |
| Meixnerite | Mg6Al2(OH)16(OH)2 · 4H2O | Trig. 3m(32/m) : R3m |
| Pyroaurite | Mg6Fe3+2(OH)16[CO3] · 4H2O | Trig. 3m(32/m) : R3m |
| Reevesite | Ni6Fe3+2(OH)16(CO3) · 4H2O | Trig. 3m(32/m) : R3m |
| Takovite | Ni6Al2(OH)16[CO3] · 4H2O | Trig. 3m(32/m) : R3m |
| 'UM2002-02-COH:FeNi' | (Fe2+,Ni)6Fe3+2(CO3)(OH)16 · 4H2O | |
| Woodallite | Mg6Cr2(OH)16Cl2 · 4H2O | Trig. 3m(32/m) : R3m |
Common Associates
Associations Based on Photo Data:
| 45 photos of Stichtite associated with Serpentine Subgroup | D3[Si2O5](OH)4 |
| 16 photos of Stichtite associated with Chromite | Fe2+Cr3+2O4 |
| 14 photos of Stichtite associated with Lizardite | Mg3(Si2O5)(OH)4 |
| 10 photos of Stichtite associated with 'Serpentinite' | |
| 10 photos of Stichtite associated with Magnesiochromite | MgCr2O4 |
| 8 photos of Stichtite associated with Aragonite | CaCO3 |
| 8 photos of Stichtite associated with Chrysotile | Mg3(Si2O5)(OH)4 |
| 6 photos of Stichtite associated with 'Stichtite-2H' | Mg6(Cr,Al)2(CO3)(OH)16 · 4H2O |
| 5 photos of Stichtite associated with Pyroaurite | Mg6Fe3+2(OH)16[CO3] · 4H2O |
| 4 photos of Stichtite associated with Magnetite | Fe2+Fe3+2O4 |
Related Minerals - Strunz-mindat Grouping
| 5.DA. | Alexkhomyakovite | K6(Ca2Na)(CO3)5Cl · 6H2O |
| 5.DA. | Amoraite | Ca12Al6(OH)36(CO3)2(SO3) · 15H2O |
| 5.DA.05 | Dypingite | Mg5(CO3)4(OH)2 · 5H2O |
| 5.DA.05 | 'UM1986-10-CO:ClHMgMnZn (also called Mineral F, Dunn, 1995)' | Mg5(Zn,Mn)3(CO3)2(OH,Cl)12 · H2O |
| 5.DA.05 | 'UM1987-01-CO:HMgS' | Mg4(CO3)2(OH)4 · 6H2O ? |
| 5.DA.05 | Giorgiosite | Mg5(CO3)4(OH)2 · 5-6H2O |
| 5.DA.05 | Hydromagnesite | Mg5(CO3)4(OH)2 · 4H2O |
| 5.DA.05 | Widgiemoolthalite | Ni5(CO3)4(OH)2 · 5H2O |
| 5.DA.10 | Artinite | Mg2(CO3)(OH)2 · 3H2O |
| 5.DA.10 | Chlorartinite | Mg2(CO3)(OH)Cl · 2H2O |
| 5.DA.10 | Indigirite | Mg2Al2(CO3)4(OH)2 · 15H2O |
| 5.DA.15 | Zaratite | Ni3(CO3)(OH)4 · 4H2O ? |
| 5.DA.15 | Otwayite | Ni2(CO3)(OH)2 · H2O |
| 5.DA.20 | Kambaldaite | NaNi4(CO3)3(OH)3 · 3H2O |
| 5.DA.25 | Callaghanite | Cu2Mg2(CO3)(OH)6 · 2H2O |
| 5.DA.30 | Claraite | (Cu,Zn)15(CO3)4(AsO4)2(SO4)(OH)14 · 7H2O |
| 5.DA.35 | Hydroscarbroite | Al14(CO3)3(OH)36 · nH2O |
| 5.DA.35 | Scarbroite | Al5(CO3)(OH)13 · 5H2O |
| 5.DA.40 | Karchevskyite | Mg18Al9(OH)54Sr2(CO3)9(H2O)6(H3O)5 |
| 5.DA.40 | 'UM1987-05-OH:AlCMg' | Mg4Al2(OH)12(CO3,SO4) · 3H2O |
| 5.DA.40 | Quintinite | Mg4Al2(OH)12(CO3) · 3H2O |
| 5.DA.40 | Charmarite | Mn2+4Al2(OH)12[CO3] · 3H2O |
| 5.DA.40 | Caresite | Fe2+4Al2(OH)12[CO3] · 3H2O |
| 5.DA.45 | 'Hydrotalcite-2H' | Mg6Al2(CO3)(OH)16 · 4H2O |
| 5.DA.45 | 'Stichtite-2H' | Mg6(Cr,Al)2(CO3)(OH)16 · 4H2O |
| 5.DA.45 | Brugnatellite | Mg6Fe3+(CO3)(OH)13 · 4H2O |
| 5.DA.45 | Zaccagnaite | Zn4Al2(OH)12[CO3] · 3H2O |
| 5.DA.45 | 'Pyroaurite-2H' | Mg6Fe3+2(OH)16(CO3) · 4H2O |
| 5.DA.45 | Liudongshengite | Zn4Cr2(OH)12(CO3) · 3H2O |
| 5.DA.45 | Chlormagaluminite | Mg4Al2(OH)12Cl2 · 3H2O |
| 5.DA.50 | Pyroaurite | Mg6Fe3+2(OH)16[CO3] · 4H2O |
| 5.DA.50 | Takovite | Ni6Al2(OH)16[CO3] · 4H2O |
| 5.DA.50 | Reevesite | Ni6Fe3+2(OH)16(CO3) · 4H2O |
| 5.DA.50 | Kaznakhtite | Ni6Co3+2(CO3)(OH)16 · 4H2O |
| 5.DA.50 | Comblainite | Ni4Co2(OH)12[CO3] · 3H2O |
| 5.DA.50 | Marioantofilliite | [Cu4Al2(OH)12](CO3) · 3H2O |
| 5.DA.50 | Hydrotalcite | Mg6Al2(CO3)(OH)16 · 4H2O |
| 5.DA.50 | Desautelsite | Mg6Mn3+2(OH)16[CO3] · 4H2O |
| 5.DA.55 | Coalingite | Mg10Fe3+2(OH)24[CO3] · 2H2O |
| 5.DA.55 | Akopovaite | Al4Li2(OH)12(CO3)(H2O)3 |
| 5.DA.60 | Šlikite | Zn2Mg(CO3)2(OH)2 · 4H2O |
| 5.DA.65 | Marklite | Cu5(CO3)2(OH)6 · 6H2O |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Stichtite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Stichtite
mindat.org URL:
https://www.mindat.org/min-3784.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Stichtite
Reference List:
Foshag, William F. (1920) The chemical composition of hydrotalcite and the hydrotalcite group of minerals. Proceedings of the United States National Museum, 58 (2329). 147-153 doi:10.5479/si.00963801.2329.147
Read, H. H., Dixon, B. E. (1933) On stichtite from Cunningsburgh, Shetland Islands. Mineralogical Magazine and Journal of the Mineralogical Society, 23 (140) 309-316 doi:10.1180/minmag.1933.023.140.03
Frondel, Clifford (1941) Constitution and polymorphism of the pyroaurite and sjögrenite groups. American Mineralogist, 26 (5) 295-315
Bookin, A. S., Cherkashin, V. I., Drits, V. A. (1993) Polytype Diversity of the Hydrotalcite-Like Minerals II. Determination of the Polytypes of Experimentally Studied Varieties. Clays and Clay Minerals, 41 (5) 558-564 doi:10.1346/ccmn.1993.0410505
Bookin, A. S., Cherkashin, V. I., Drits, V. A. (1993) Reinterpretation of the X-Ray Diffraction Patterns of Stichtite and Reevesite. Clays and Clay Minerals, 41 (5) 631-634 doi:10.1346/ccmn.1993.0410514
Mondal, S. K., Baidya, T. K. (1996) Stichtite [Mg6Cr2(OH)16CO3·4H2O] in Nausahi ultramafites, Orissa, India - its transformation at elevated temperatures. Mineralogical Magazine, 60 (402) 836-840 doi:10.1180/minmag.1996.060.402.16
Ashwal, Lewis D., Cairncross, Bruce (1997) Mineralogy and origin of stichtite in chromite-bearing serpentinites. Contributions to Mineralogy and Petrology, 127 (1) 75-86 doi:10.1007/s004100050266
Mills, S. J., Whitfield, P. S., Wilson, S. A., Woodhouse, J. N., Dipple, G. M., Raudsepp, M., Francis, C. A. (2011) The crystal structure of stichtite, re-examination of barbertonite, and the nature of polytypism in MgCr hydrotalcites. American Mineralogist, 96 (1) 179-187 doi:10.2138/am.2011.3531
Mills, S. J.; Christy, A. G.; Génin, J.-M. R.; Kameda, T.; Colombo, F. (2012) Nomenclature of the hydrotalcite supergroup: natural layered double hydroxides. Mineralogical Magazine, 76 (5). 1289-1336 doi:10.1180/minmag.2012.076.5.10
Localities for Stichtite
Showing 64 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
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Tunnel Hill Quarry, Serpentine Hill, North Dundas, Zeehan mining district, West Coast municipality, Tasmania, Australia