Defernite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Defernite
Jacques Deferne
Formula:
Ca6(CO3)1.58(Si2O7)0.21(OH)7[Cl0.50(OH)0.08(H2O)0.42]
Formerly given as Ca6(CO3)2-x(SiO4)x(OH)7(Cl,OH)1-2x (x < 0.5).
Colour:
Colourless (original occurrence), also deep red, rose-brown
Lustre:
Sub-Vitreous, Waxy
Hardness:
3
Specific Gravity:
2.34 - 2.5
Crystal System:
Orthorhombic
Name:
Named by Halil Sarp, M. F. Taner, Jacques Deferne, Helene Bizouard, and B. W. Liebich in 1980 in honor of Jacques Deferne (b. 1935, Geneva, Switzerland), Curator of Mineralogy, Museum of Natural History, Geneva, Switzerland.
Type Locality:
This page provides mineralogical data about Defernite.
Unique Identifiers
Mindat ID:
1246
Long-form identifier:
mindat:1:1:1246:7
Similar Names
| Dufrénite | A valid IMA mineral species - grandfathered | Ca0.5Fe2+Fe53+(PO4)4(OH)6 · 2H2O |
IMA Classification of Defernite
Approved
Approval year:
1978
First published:
1980
Classification of Defernite
5.BA.25
5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H2O
A : With Cu, Co, Ni, Zn, Mg, Mn
5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H2O
A : With Cu, Co, Ni, Zn, Mg, Mn
16b.4.2.1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
4 : AmBn(XO3)pZqxH2O & with (m+n):p = 3:1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
4 : AmBn(XO3)pZq
12.1.5
12 : Carbonates with other anions
1 : Carbonates with halides
12 : Carbonates with other anions
1 : Carbonates with halides
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 |
|---|---|---|
| Def | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Def | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Defernite
Sub-Vitreous, Waxy
Transparency:
Transparent
Colour:
Colourless (original occurrence), also deep red, rose-brown
Comment:
Red to rose brown colors probably due to Mn.
Streak:
Colorless, also Pink
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
perfect {010} and distinct {100}
perfect {010} and distinct {100}
Fracture:
Splintery, Conchoidal
Density:
2.34 - 2.5 g/cm3 (Measured) 2.31 g/cm3 (Calculated)
Comment:
Calculated D = 2.42 from type locaity
Optical Data of Defernite
Type:
Biaxial (-)
RI values:
nα = 1.546 nβ = 1.572 nγ = 1.576
2V:
Measured: 42° , Calculated: 42°
Birefringence:
0.030
Max. Birefringence:
δ = 0.030
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 (positive)
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 biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
medium r < v (Turkey)
Optical Extinction:
Parallel. X = c, Y = b
Pleochroism:
Strong
Comments:
X = ochre-brown,
Y= brownish-orange to ochre-brown,
Z= colorless to yellow
Y= brownish-orange to ochre-brown,
Z= colorless to yellow
Chemistry of Defernite
Mindat Formula:
Ca6(CO3)1.58(Si2O7)0.21(OH)7[Cl0.50(OH)0.08(H2O)0.42]
Formerly given as Ca6(CO3)2-x(SiO4)x(OH)7(Cl,OH)1-2x (x < 0.5).
Formerly given as Ca6(CO3)2-x(SiO4)x(OH)7(Cl,OH)1-2x (x < 0.5).
Element Weights:
Common Impurities:
Fe,Mn,Mg
Crystallography of Defernite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 17.860 Å, b = 22.775 Å, c = 3.658 Å
Ratio:
a:b:c = 0.784 : 1 : 0.161
Unit Cell V:
1,487.93 ų (Calculated from Unit Cell)
Z:
8
Morphology:
idiomorphic "porphyroblastic" laths
Comment:
space group Pna2, or Pnam
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0001795 | Defernite | Armbruster T, Yang P, Liebich B W (1996) Mechanism of the SiO4 for CO3 substitution in defernite, Ca6(CO3)1.58(Si2O7)0.21(OH)7[Cl0.50(OH)0.08(H2O)0.42]: A single-crystal X-ray study at 100 K American Mineralogist 81 625-631 |  | 1996 | 0 | 293 | |
| 0001193 | Defernite | Peacor D R, Sarp H, Dunn P J, Innes J, Nelen J A (1988) Defernite from the Kombat mine, Namibia: A second occurence, structure refinement, and crystal chemistry American Mineralogist 73 888-893 | | 1988 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.37 Å | (100) |
| 8.29 Å | (35) |
| 5.68 Å | (30) |
| 3.045 Å | (40) |
| 2.899 Å | (50) |
| 2.418 Å | (35) |
| 1.962 Å | (35) |
| 1.825 Å | (40) |
Comments:
Sarp et al. (1980)
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47g : [Halogen-bearing surface weathering minerals] |
Geological Setting:
Primary, glassy subhedral grains intergrown primarily with hausmannite.
Type Occurrence of Defernite
General Appearance of Type Material:
Small subiodiomorphic to idiomorphic crystals, 100-200 µm in length and fibro-radiating patches.
Place of Conservation of Type Material:
Museum of Natural History, Geneva, Switzerland, 435/30; National Museum of Natural History, Washington, D.C., USA, 163241. Cotype material in NHM Vienna collection (M 5134).
Geological Setting of Type Material:
Secondary alteration product of high-temperature calc-silicates. In skarn produced by a granitic intrusion into limestone.
Associated Minerals at Type Locality:
Synonyms of Defernite
Other Language Names for Defernite
Common Associates
Associations Based on Photo Data:
| 12 photos of Defernite associated with Hausmannite | Mn2+Mn3+2O4 |
| 9 photos of Defernite associated with Hematite | Fe2O3 |
| 6 photos of Defernite associated with Native Copper | Cu |
| 4 photos of Defernite associated with Jaffeite | Ca6(Si2O7)(OH)6 |
Related Minerals - Strunz-mindat Grouping
| 5.BA.05 | Azurite | Cu3(CO3)2(OH)2 |
| 5.BA.10 | Mcguinnessite | (Mg,Cu)2(CO3)(OH)2 |
| 5.BA.10 | Zincrosasite | (Zn,Cu)2(CO3)(OH)2 |
| 5.BA.10 | Parádsasvárite | Zn2(CO3)(OH)2 |
| 5.BA.10 | Rosasite | (Cu,Zn)2(CO3)(OH)2 |
| 5.BA.10 | Nullaginite | Ni2(CO3)(OH)2 |
| 5.BA.10 | Georgeite | [Cu(OH)2-x(H2O)x][CO3]x/2 |
| 5.BA.10 | Glaukosphaerite | (Cu,Ni)2(CO3)(OH)2 |
| 5.BA.10 | Pokrovskite | Mg2(CO3)(OH)2 |
| 5.BA.10 | Kolwezite | CuCo(CO3)(OH)2 |
| 5.BA.10 | Chukanovite | Fe2+2(CO3)(OH)2 |
| 5.BA.10 | Malachite | Cu2(CO3)(OH)2 |
| 5.BA.10 | Perchiazziite | Co2(CO3)(OH)2 |
| 5.BA.15 | Aurichalcite | (Zn,Cu)5(CO3)2(OH)6 |
| 5.BA.15 | Hydrozincite | Zn5(CO3)2(OH)6 |
| 5.BA.20 | Holdawayite | Mn6(CO3)2(OH)7(Cl,OH) |
| 5.BA.25 | 'UM1977-03-COSiO:CaClH' | Ca10-11(CO3)7(SiO4)Cl1-2(OH)1-2 |
| 5.BA.30 | Sclarite | Zn7(CO3)2(OH)10 |
| 5.BA.30 | Loseyite | (Mn2+,Zn,Mg)4Zn3(CO3)2(OH)10 |
Other Information
Notes:
Dissolves in l:l HCl with effervescence
Special Storage/
Display Requirements:
Display Requirements:
On exposure, the cleavage surfaces of defernite laths develop a whitish patina.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Defernite
mindat.org URL:
https://www.mindat.org/min-1246.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 Defernite
Reference List:
Sarp, Halil, Taner, Mehmet Fevzi, Deferne, Jacques, Bizouard, Hélène, Liebich, Bernard W. (1980) La defernite, Ca6(CO3)2(OH, Cl)8 •nH2O, un nouveau carbonate de calcium chloro-hydroxylé. Bulletin de Minéralogie, 103 (2) 185-189 doi:10.3406/bulmi.1980.7395
Fleischer, M., Cabri, L. J., Chao, G. Y., Pabst, A. (1980) New mineral names. American Mineralogist, 65 (9-10). 1065-1070 p.1066
Sarp, Halil, Taner, Mehmet Fevzi, Deferne, Jacques, Bizouard, Hélène, Liebich, Bernard W. (1980) La defernite, Ca6(CO3)2(OH, Cl)8 •nH2O, un nouveau carbonate de calcium chloro-hydroxylé. Bulletin de Minéralogie, 103 (2) 185-189 doi:10.3406/bulmi.1980.7395
Localities for Defernite
Showing 2 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.
Namibia | |
| Peacor et al. (1988) +1 other reference |
Turkey (TL) | |
| Bull.Soc.fr.Min.Crist. (1980) +3 other references |
Quick NavTopAbout DeferniteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Kombat Mine, Kombat, Otavi Constituency, Otjozondjupa Region, Namibia