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Clinohumite
A valid IMA mineral species - grandfathered
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About Clinohumite
Formula:
Mg9(SiO4)4F2
a n=4 member of the humite polysomatic series
Colour:
White; yellow to brown with increasing Ti; orange; pinkish
Hardness:
6
Specific Gravity:
3.17 - 3.35
Crystal System:
Monoclinic
Member of:
Name:
Named in 1876 Alfred Lewis Oliver Legrand Des Cloizeaux in allusion to its monoclinic crystal structure and relationship to humite, which was named after Sir Abraham Hume [February 20, 1749 London, England, UK – March 24, 1838 Wormley Bury. England. UK], English connoisseur and collector of gems, minerals, and artwork.
Type Locality:
Clinohumite is a monoclinic member of the humite group. It forms a continuous series towards hydroxylclinohumite. The name "clinohumite" has commonly been used as a default when the F/OH ratio has not been determined. Since hydroxylclinohumite was approved as a separate mineral (1998) it has become apparent that hydroxylclinohumite is much more common than indicated in the literature and locality entries in Mindat. It should also be noted that some of the published analyses (Luc Yen, Vietnam and Kukh-i-Lal, Tajikistan) are very close to the borderline between the two minerals, and both of these minerals are probably present at many localities.
Clinohumite may contain some Ti and the varietal name titanclinohumite (older literature uses the name "titanolivine" for this variety) is commonly used.
Clinohumite is often found associated with spinel in magnesium-rich skarns. This is the most common type of occurrence, but clinohumite is also known from other environments such as in volcanic ejecta, in metamorphosed peridotites and in alkaline-ultrabasic complexes. Clinohumite is often formed as a replacement of forsterite.
It is difficult to distinguish minerals in the humite-group, as they largely occur in the same environments and localities. Their physical and optical appearances are also similar, as is the occurrence of rounded crystals or anhedral grains. A quantitative chemical analysis (microprobe) combined with structural analyses (XRD) seem to be required to identify individual humite group species with absolute certainty. It is therefore quite possible that some of the locality entries and photos may be incorrectly identified as clinohumite.
Visit gemdat.org for gemological information about Clinohumite.
Clinohumite may contain some Ti and the varietal name titanclinohumite (older literature uses the name "titanolivine" for this variety) is commonly used.
Clinohumite is often found associated with spinel in magnesium-rich skarns. This is the most common type of occurrence, but clinohumite is also known from other environments such as in volcanic ejecta, in metamorphosed peridotites and in alkaline-ultrabasic complexes. Clinohumite is often formed as a replacement of forsterite.
It is difficult to distinguish minerals in the humite-group, as they largely occur in the same environments and localities. Their physical and optical appearances are also similar, as is the occurrence of rounded crystals or anhedral grains. A quantitative chemical analysis (microprobe) combined with structural analyses (XRD) seem to be required to identify individual humite group species with absolute certainty. It is therefore quite possible that some of the locality entries and photos may be incorrectly identified as clinohumite.
Visit gemdat.org for gemological information about Clinohumite.Unique Identifiers
Mindat ID:
1077
Long-form identifier:
mindat:1:1:1077:7
Similar Names
| Clinohumite-OH | A synonym of Hydroxylclinohumite |
IMA Classification of Clinohumite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1876
Classification of Clinohumite
9.AF.55
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
52.3.2d.1
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
3 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] coordination only
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
3 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] coordination only
17.1.12
17 : Silicates Containing other Anions
1 : Silicates with fluoride (not containing Al)
17 : Silicates Containing other Anions
1 : Silicates with fluoride (not containing Al)
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 |
|---|---|---|
| Chu | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Chu | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Chu | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
| Chu | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Chu | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Clinohumite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Clinohumite
Colour:
White; yellow to brown with increasing Ti; orange; pinkish
Hardness:
6 on Mohs scale
Cleavage:
Poor/Indistinct
Cleavage on {100}.
Cleavage on {100}.
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
3.17 - 3.35 g/cm3 (Measured) 3.279 g/cm3 (Calculated)
Comment:
Depends mainly on Mg:Fe ratio and O:F ratio.
Optical Data of Clinohumite
Type:
Biaxial (+)
RI values:
nα = 1.623 - 1.702 nβ = 1.636 - 1.709 nγ = 1.651 - 1.728
2V:
Measured: 52° to 90°, Calculated: 64° to 88°
Max. Birefringence:
δ = 0.026 - 0.028
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:
Very High (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:
weak
Chemistry of Clinohumite
Mindat Formula:
Mg9(SiO4)4F2
a n=4 member of the humite polysomatic series
a n=4 member of the humite polysomatic series
Element Weights:
Elements listed:
Common Impurities:
Fe,Ti,Al,Mn,Ca,(OH)
Chemical Analysis
Empirical formulas:
| Sample ID | Empirical Formula |
|---|---|
| 1 | Mg8.805Fe0.006Ti0.214(Si0.993O4)4O0.42F0.76(OH)0.82. |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Kukh-i-Lal, Ishkoshim, Gorno-Badakhshan, Tajikistan |
Crystallography of Clinohumite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/c
Setting:
P21/c
Cell Parameters:
a = 13.71 Å, b = 4.75 Å, c = 10.29 Å
β = 100.83°
β = 100.83°
Ratio:
a:b:c = 2.886 : 1 : 2.166
Unit Cell V:
658.18 ų (Calculated from Unit Cell)
Twinning:
Common on {100}, simple, lamellar.
Crystallographic forms of Clinohumite
Crystal Atlas:
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Clinohumite no.27 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by
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Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0002663 | Clinohumite | Friedrich A, Lager G A, Kunz M, Chakoumakos B C, Smyth J R, Schultz A J (2001) Temperature-dependent single-crystal neutron diffraction study of natural chondrodite and clinohumite American Mineralogist 86 981-989 |  | 2001 | 0 | 295 | |
| 0002338 | Clinohumite | Ottolini L, Camara F, Bigi S (2000) An investigation of matrix effects in the analysis of fluorine in humite-group minerals by EMPA, SIMS, and SREF American Mineralogist 85 89-102 | | 2000 | 0 | 293 | |
| 0002664 | Clinohumite | Friedrich A, Lager G A, Kunz M, Chakoumakos B C, Smyth J R, Schultz A J (2001) Temperature-dependent single-crystal neutron diffraction study of natural chondrodite and clinohumite American Mineralogist 86 981-989 | | 2001 | 0 | 100 | |
| 0002665 | Clinohumite | Friedrich A, Lager G A, Kunz M, Chakoumakos B C, Smyth J R, Schultz A J (2001) Temperature-dependent single-crystal neutron diffraction study of natural chondrodite and clinohumite American Mineralogist 86 981-989 | | 2001 | 0 | 20 |
CIF Raw Data - click here to close
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 |
|---|---|
| 5.02 Å | (70) |
| 3.70 Å | (70) |
| 2.76 Å | (70) |
| 2.54 Å | (70) |
| 2.51 Å | (70) |
| 2.26 Å | (70) |
| 1.738 Å | (100) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 7 : Ultramafic igneous rocks | |
| High-𝑇 alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 36 : Carbonatites, kimberlites, and related igneous rocks | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Clinohumite
Other Language Names for Clinohumite
Dutch:Clinohumiet
German:Klinohumit
Clinohumit
Clinohumit
Russian:Клиногумит
Simplified Chinese:斜硅镁石
Spanish:Clinohumita
Traditional Chinese:斜矽鎂石
Relationship of Clinohumite to other Species
Member of:
Other Members of Humite Subgroup:
| Chondrodite | Mg5(SiO4)2F2 | Mon. 2/m : P21/c |
| Humite | Mg7(SiO4)3F2 | Orth. mmm(2/m2/m2/m) : Pnma |
| Hydroxylchondrodite | Mg5(SiO4)2(OH)2 | Mon. 2/m : P21/c |
| Hydroxylclinohumite | Mg9(SiO4)4(OH)2 | Mon. 2/m : P21/c |
| Norbergite | Mg3(SiO4)F2 | Orth. mmm(2/m2/m2/m) |
| 'Unnamed (OH-analogue of humite)' | Mg7(SiO4)3(OH)2 | Orth. |
Common Associates
Associations Based on Photo Data:
| 89 photos of Clinohumite associated with Spinel | MgAl2O4 |
| 40 photos of Clinohumite associated with Calcite | CaCO3 |
| 9 photos of Clinohumite associated with Graphite | C |
| 5 photos of Clinohumite associated with Phlogopite | KMg3(AlSi3O10)(OH)2 |
| 5 photos of Clinohumite associated with Ludwigite | Mg2Fe3+(BO3)O2 |
| 4 photos of Clinohumite associated with Forsterite | Mg2(SiO4) |
| 3 photos of Clinohumite associated with 'Chrome-Tremolite' | ◻{Ca2}{Mg5}(Si8O22)(OH)2 |
| 3 photos of Clinohumite associated with Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| 3 photos of Clinohumite associated with Szaibélyite | MgBO2(OH) |
| 3 photos of Clinohumite associated with Dolomite | CaMg(CO3)2 |
Related Minerals - Strunz-mindat Grouping
| 9.AF. | Chegemite | Ca7(SiO4)3(OH)2 |
| 9.AF. | Jingwenite-(Y) | YAlV4+(SiO4)O2(OH)2 |
| 9.AF. | Barwoodite | Mn2+6Nb5+(SiO4)2O3(OH)3 |
| 9.AF.05 | Sillimanite | Al2(SiO4)O |
| 9.AF.05 | 'Xenolite' | Al10Si8O31 |
| 9.AF.10 | Kanonaite | Mn3+Al(SiO4)O |
| 9.AF.10 | Andalusite | Al2(SiO4)O |
| 9.AF.15 | Kyanite | Al2(SiO4)O |
| 9.AF.20 | Krieselite | Al2(GeO4)F2 |
| 9.AF.20 | Mullite | Al4+2xSi2-2xO10-x |
| 9.AF.23 | Boromullite | Al9BSi2O19 |
| 9.AF.25 | Yoderite | Mg(Al,Fe3+)3(SiO4)2O(OH) |
| 9.AF.30 | Zincostaurolite | Zn2Al9Si4O23(OH) |
| 9.AF.30 | Staurolite | Fe2+2Al9Si4O23(OH) |
| 9.AF.30 | Magnesiostaurolite | Mg(Mg,Li)3(Al,Mg)18Si8O44(OH)4 |
| 9.AF.35 | Topaz | Al2(SiO4)(F,OH)2 |
| 9.AF.40 | Norbergite | Mg3(SiO4)F2 |
| 9.AF.45 | Chondrodite | Mg5(SiO4)2F2 |
| 9.AF.45 | Kumtyubeite | Ca5(SiO4)2F2 |
| 9.AF.45 | Reinhardbraunsite | Ca5(SiO4)2(OH,F)2 |
| 9.AF.45 | Hydroxylchondrodite | Mg5(SiO4)2(OH)2 |
| 9.AF.45 | Alleghanyite | Mn2+5(SiO4)2(OH)2 |
| 9.AF.50 | 'Unnamed (Ca-analogue of Humite)' | Ca7(SiO4)4F2 |
| 9.AF.50 | Humite | Mg7(SiO4)3F2 |
| 9.AF.50 | Manganhumite | Mn2+7(SiO4)3(OH)2 |
| 9.AF.50 | 'Unnamed (OH-analogue of humite)' | Mg7(SiO4)3(OH)2 |
| 9.AF.50 | Fluorchegemite | Ca7(SiO4)3F2 |
| 9.AF.55 | Hydroxylclinohumite | Mg9(SiO4)4(OH)2 |
| 9.AF.55 | Sonolite | Mn2+9(SiO4)4(OH)2 |
| 9.AF.60 | Leucophoenicite | Mn2+7(SiO4)3(OH)2 |
| 9.AF.65 | Ribbeite | Mn2+5(SiO4)2(OH)2 |
| 9.AF.70 | Jerrygibbsite | Mn2+9(SiO4)4(OH)2 |
| 9.AF.75 | Franciscanite | Mn2+6(V5+,◻)2(SiO4)2(O,OH)6 |
| 9.AF.75 | Scorticoite | Mn6(Sb,◻)Σ2(SiO4)2O3(OH)3 |
| 9.AF.75 | Welinite | Mn2+6(W6+,Mg)2(SiO4)2(O,OH)6 |
| 9.AF.75 | Örebroite | Mn2+3(Sb5+,Fe3+)(SiO4)(O,OH)3 |
| 9.AF.80 | Ellenbergerite | Mg6(Mg,Ti,Zr,◻)2(Al,Mg)6Si8O28(OH)10 |
| 9.AF.85 | Magnesiochloritoid | MgAl2O(SiO4)(OH)2 |
| 9.AF.85 | Ottrélite | Mn2+Al2O(SiO4)(OH)2 |
| 9.AF.85 | Chloritoid | Fe2+Al2O(SiO4)(OH)2 |
| 9.AF.90 | Olmiite | CaMn2+[SiO3(OH)](OH) |
| 9.AF.90 | Poldervaartite | CaCa[SiO3(OH)](OH) |
| 9.AF.95 | Pilawite-(Y) | Ca2Y2Al4(SiO4)4O2(OH)2 |
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.
Clinohumite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Clinohumite
mindat.org URL:
https://www.mindat.org/min-1077.html
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Please feel free to link to this page.
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References for Clinohumite
Reference List:
Robinson, Keith, Gibbs, G. V., Ribbe, and Paul H. (1973) The crystal structures of the humite minerals. IV. Clinohumite and titanoclinohumite. American Mineralogist, 58 (1-2) 43-49
Ottolini, Luisa, Cámara, Fernando, Bigi, Simona (2000) An investigation of matrix effects in the analysis of fluorine in humite-group minerals by EMPA, SIMS, and SREF. American Mineralogist, 85 (1) 89-102 doi:10.2138/am-2000-0110
Ferraris, Giovanni, Prencipe, M., Sokolova, E., Gekimyants, V.M., Spiridonov, E.M. (2000) Hydroxylclinohumite, a new member of the humite group: Twinning, crystal structure and crystal chemistry of the clinohumite subgroup. Zeitschrift für Kristallographie - Crystalline Materials, 215 (3). 169-173 doi:10.1524/zkri.2000.215.3.169
Pawley, Alison (2000) Stability of clinohumite in the system MgO-SiO2-H2O. Contributions to Mineralogy and Petrology, 138 (3) 284-291 doi:10.1007/s004100050563
Anzahamazonono, Madagascar