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Silicocarnotite
A valid IMA mineral species
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Marie-Adolphe Carnot
Formula:
Ca5[(SiO4)(PO4)](PO4)
May also be written Ca5SiP2O12 or Ca5(PO4)2SiO4.
Colour:
Colourless (natural); blue (synthetic)
Lustre:
Vitreous
Hardness:
5
Specific Gravity:
3.063 (Calculated)
Crystal System:
Orthorhombic
Name:
Synthetic material was discovered in slag by Adolphe Carnot and A. Richard in 1883. The material was named by Kroll in 1911 after Carnot. The name silicocarnotite has been used for the synthetic phase Ca5[(SiO4)(PO4)](PO)4 since then. The natural mineral was described by Galuskin et al. in 2016 and they kept the same name.
Marie Adolphe Carnot (27 January 1839, Paris, France – 20 June 1920) was a French chemist, mining engineer and politician. He was a chemistry professor at École des Mines in Paris and later Chief Engineer of Mines and Inspector General of Mines, becoming Dean of the École Nationale des Mines in 1901-1907, when he retired. The unrelated mineral carnotite is also named after him.
Marie Adolphe Carnot (27 January 1839, Paris, France – 20 June 1920) was a French chemist, mining engineer and politician. He was a chemistry professor at École des Mines in Paris and later Chief Engineer of Mines and Inspector General of Mines, becoming Dean of the École Nationale des Mines in 1901-1907, when he retired. The unrelated mineral carnotite is also named after him.
Co-Type Localities:
Dimorph of:
Isotypic with ternesite. A member of the ternesite-silicocarnotite solid solution. Chemically similar to nagelschmidtite and 'ciplyite'.
Known for a long time as an artificial, calcium silico-phosphate in slag.
Natural material was found within the Hatrurim Complex. It is result of pyrometamorphism, and more specifically an interaction of primary "clinker minerals" (flamite, fluorellestadite-fluorapatite, larnite) with sulphate-bearing melts.
Known for a long time as an artificial, calcium silico-phosphate in slag.
Natural material was found within the Hatrurim Complex. It is result of pyrometamorphism, and more specifically an interaction of primary "clinker minerals" (flamite, fluorellestadite-fluorapatite, larnite) with sulphate-bearing melts.
Unique Identifiers
Mindat ID:
9647
Long-form identifier:
mindat:1:1:9647:4
IMA Classification of Silicocarnotite
Approved
IMA Formula:
Ca5(PO4)2(SiO4)
Approval year:
2013
First published:
2016
Type description reference:
Galuskin, Evgeny V., Galuskina, Irina O., Gfeller, Frank, Krüger, Biljana, Kusz, Joachim, Vapnik, Yevgeny, Dulski, Mateusz, Dzierżanowski, Piotr (2016) Silicocarnotite, Ca5[(SiO4)(PO4)](PO4), a new ,,old'' mineral from the Negev Desert, Israel, and the ternesite–silicocarnotite solid solution: indicators of high-temperature alteration of pyrometamorphic rocks of the Hatrurim Complex, Southern Levant. European Journal of Mineralogy, 28 (1) 105-123 doi:10.1127/ejm/2015/0027-2494
Classification of Silicocarnotite
9.AH.20
9 : SILICATES (Germanates)
A : Nesosilicates
H : Nesosilicates with CO3, SO4, PO4, etc.
9 : SILICATES (Germanates)
A : Nesosilicates
H : Nesosilicates with CO3, SO4, PO4, etc.
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 |
|---|---|---|
| Scnt | 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 Silicocarnotite
Vitreous
Transparency:
Transparent
Colour:
Colourless (natural); blue (synthetic)
Streak:
White
Hardness:
5 on Mohs scale
Hardness:
VHN50=537 kg/mm2 - Vickers
Comment:
ca. 5
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
Not observed
Fracture:
Irregular/Uneven
Density:
3.063(1) g/cm3 (Calculated)
Optical Data of Silicocarnotite
Type:
Biaxial (+)
RI values:
nα = 1.618(2) nβ = 1.621(2) nγ = 1.628(2)
2V:
Measured: 75° (5), Calculated: 67°
Max. Birefringence:
δ = 0.010
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
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)
Pleochroism:
Non-pleochroic