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Chegemite
A valid IMA mineral species
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About Chegemite
Formula:
Ca7(SiO4)3(OH)2
Colour:
Pink, yellow-pink to white.
Hardness:
5½ - 6
Specific Gravity:
2.86
Crystal System:
Orthorhombic
Member of:
Name:
from the Chegem River where the new mineral was discovered in the headwater tributary-area
Type Locality:
Isostructural with:
Unique Identifiers
Mindat ID:
39004
Long-form identifier:
mindat:1:1:39004:2
IMA Classification of Chegemite
Approved
Approval year:
2008
First published:
2009
Type description reference:
Galuskin, Evgeny V., Gazeev, Viktor M., Lazic, Biljana, Armbruster, Thomas, Galuskina, Irina O., Zadov, Aleksander E., Pertsev, Nikolai N., Wrzalik, Roman, Dzierżanowski, Piotr, Gurbanov, Anatoly G., Bzowska, Grażyna (2009) Chegemite Ca7(SiO4)3(OH)2 a new humite-group calcium mineral from the Northern Caucasus, Kabardino-Balkaria, Russia. European Journal of Mineralogy, 21 (5) 1045-1059 doi:10.1127/0935-1221/2009/0021-1962
Classification of Chegemite
9.AF.
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
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Cgm | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Chegemite
Colour:
Pink, yellow-pink to white.
Streak:
White
Hardness:
5½ - 6 on Mohs scale
Hardness:
VHN100=315 - Vickers
Cleavage:
Imperfect/Fair
(010)
(010)
Fracture:
Conchoidal
Density:
2.86(1) g/cm3 (Measured) 2.892 g/cm3 (Calculated)
Optical Data of Chegemite
Type:
Biaxial
RI values:
nα = 1.621(2) nβ = 1.626(3) nγ = 1.630(2)
2V:
Measured: -81° (5), Calculated: -78°
Max. Birefringence:
δ = 0.009
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:
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
Optical Extinction:
X = a, Y = b, Z = c
Chemistry of Chegemite
Mindat Formula:
Ca7(SiO4)3(OH)2
Element Weights:
Elements listed:
Crystallography of Chegemite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Setting:
Pbnm
Cell Parameters:
a = 5.0696(1) Å, b = 11.3955(1) Å, c = 23.557(3) Å
Ratio:
a:b:c = 0.445 : 1 : 2.067
Unit Cell V:
1360.91 ų
Z:
4
Twinning:
Twins, probably on (110)
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.611 Å | (43) |
| 3.646 Å | (41) |
| 3.041 Å | (65) |
| 2.837 Å | (60) |
| 2.728 Å | (74) |
| 2.557 Å | (43) |
| 2.520 Å | (59) |
| 1.910 Å | (100) |
Reference:
Galuskin, Evgeny V., Gazeev, Viktor M., Lazic, Biljana, Armbruster, Thomas, Galuskina, Irina O., Zadov, Aleksander E., Pertsev, Nikolai N., Wrzalik, Roman, Dzierżanowski, Piotr, Gurbanov, Anatoly G., Bzowska, Grażyna (2009) Chegemite Ca7(SiO4)3(OH)2 a new humite-group calcium mineral from the Northern Caucasus, Kabardino-Balkaria, Russia. European Journal of Mineralogy, 21 (5) 1045-1059 doi:10.1127/0935-1221/2009/0021-1962
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 9 : Lava/xenolith minerals (hornfels, sanidinite facies) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 51 : Pyrometamorphic minerals (see also #54 and #56) | <0.36 |
Type Occurrence of Chegemite
General Appearance of Type Material:
Granular aggregates with grain sizes up to 5 mm.
Place of Conservation of Type Material:
Fersman Mineralogical Museum in Moscow, Russia, with the number 3731/1 and the single grain used for structural investigation is deposited in the Museum of Natural History in Bern, Switzerland, with the number NMBE 39571.
Geological Setting of Type Material:
A rock-forming mineral in high-temperature skarns (sanadinite) in calcareous xenoliths in ignimbrites.
Associated Minerals at Type Locality:
Reference:
Galuskin, Evgeny V., Gazeev, Viktor M., Lazic, Biljana, Armbruster, Thomas, Galuskina, Irina O., Zadov, Aleksander E., Pertsev, Nikolai N., Wrzalik, Roman, Dzierżanowski, Piotr, Gurbanov, Anatoly G., Bzowska, Grażyna (2009) Chegemite Ca7(SiO4)3(OH)2 a new humite-group calcium mineral from the Northern Caucasus, Kabardino-Balkaria, Russia. European Journal of Mineralogy, 21 (5) 1045-1059 doi:10.1127/0935-1221/2009/0021-1962
Synonyms of Chegemite
Other Language Names for Chegemite
Relationship of Chegemite to other Species
Member of:
Other Members of Chegemite Subgroup:
| Edgrewite | Ca9(SiO4)4F2 | Mon. 2/m : P21/c |
| Fluorchegemite | Ca7(SiO4)3F2 | Orth. mmm(2/m2/m2/m) : Pnma |
| Hydroxyledgrewite | Ca9(SiO4)4(OH)2 | Mon. 2/m : P21/c |
| Kumtyubeite | Ca5(SiO4)2F2 | Mon. 2/m : P21/c |
| Reinhardbraunsite | Ca5(SiO4)2(OH,F)2 | Mon. 2/m : P21/c |
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 3 photos of Chegemite associated with Larnite | Ca2SiO4 |
| 2 photos of Chegemite associated with Hillebrandite | Ca2(SiO3)(OH)2 |
| 1 photo of Chegemite associated with 'Hydrogarnet' | |
| 1 photo of Chegemite associated with Rondorfite | Ca8Mg(SiO4)4Cl2 |
Related Minerals - Strunz-mindat Grouping
| 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 | Clinohumite | Mg9(SiO4)4F2 |
| 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.
Internet Links for Chegemite
mindat.org URL:
https://www.mindat.org/min-39004.html
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References for Chegemite
Reference List:
Galuskin, Evgeny V., Gazeev, Viktor M., Lazic, Biljana, Armbruster, Thomas, Galuskina, Irina O., Zadov, Aleksander E., Pertsev, Nikolai N., Wrzalik, Roman, Dzierżanowski, Piotr, Gurbanov, Anatoly G., Bzowska, Grażyna (2009) Chegemite Ca7(SiO4)3(OH)2 a new humite-group calcium mineral from the Northern Caucasus, Kabardino-Balkaria, Russia. European Journal of Mineralogy, 21 (5) 1045-1059 doi:10.1127/0935-1221/2009/0021-1962
Localities for Chegemite
Showing 3 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.
Russia | |
| Bailau +2 other references |
| Galuskin +9 other references |
| Galuskin +10 other references |
Quick NavTopAbout ChegemiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Lakargi Mountain, Upper Chegem volcanic caldera, Chegemsky District, Kabardino-Balkaria, Russia