Unnamed (Monoclinic Polymorph of Calcium Carbonate)
Valid as an unnamed mineral
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The original paper/mention is discussed: "The origin seems to have been strictly organic, thus disqualifying the compound as a mineral". This seems strange as the material seems to be of a natural origin.
Crystallographical data is in a good agreement with corresponding synthetic analogue that is known to form at high pressure (15 kbar) and room temperature.
From a coral, in a deep-water environment with a relatively high hydrostatic pressure.
Chemical data wt.%, analysis approximated as it is artificially normalized to 100%:
Na2O 0.55
K2O 0.10
CaO 47.20
MgO 6.26
SrO 0.37
V2O5 0.04
Fe2O3 0.04
Al2O3 0.11
P2O5 0.05
SiO2 0.14
CO2 44.14
This corresponds to (Ca0.84Mg0.16)CO3.
Crystallographical data is in a good agreement with corresponding synthetic analogue that is known to form at high pressure (15 kbar) and room temperature.
From a coral, in a deep-water environment with a relatively high hydrostatic pressure.
Chemical data wt.%, analysis approximated as it is artificially normalized to 100%:
Na2O 0.55
K2O 0.10
CaO 47.20
MgO 6.26
SrO 0.37
V2O5 0.04
Fe2O3 0.04
Al2O3 0.11
P2O5 0.05
SiO2 0.14
CO2 44.14
This corresponds to (Ca0.84Mg0.16)CO3.
Unique Identifiers
Mindat ID:
55015
Long-form identifier:
mindat:1:1:55015:8
IMA Classification of Unnamed (Monoclinic Polymorph of Calcium Carbonate)
IMA status notes:
Unnamed (probably valid)
Physical Properties of Unnamed (Monoclinic Polymorph of Calcium Carbonate)
Density:
2.76 g/cm3 (Measured) 2.82 g/cm3 (Calculated)
Chemistry of Unnamed (Monoclinic Polymorph of Calcium Carbonate)
Mindat Formula:
CaCO3
Element Weights:
Elements listed:
Crystallography of Unnamed (Monoclinic Polymorph of Calcium Carbonate)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 6.290(2) Å, b = 4.934(2) Å, c = 7.979(3) Å
β = 107.571(2)°
β = 107.571(2)°
Ratio:
a:b:c = 1.275 : 1 : 1.617
Unit Cell V:
236.07 ų (Calculated from Unit Cell)
Z:
4
Comment:
from a Rietveld refinement
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.994 Å | (100) |
| 2.4655 Å | (15) |
| 1.8861 Å | (25) |
| 1.8514 Å | (15) |
Locality:
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 Unnamed (Monoclinic Polymorph of Calcium Carbonate)
mindat.org URL:
https://www.mindat.org/min-55015.html
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References for Unnamed (Monoclinic Polymorph of Calcium Carbonate)
Localities for Unnamed (Monoclinic Polymorph of Calcium Carbonate)
Showing 1 localities.
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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.
South China Sea | |
