Takedaite
A valid IMA mineral species
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About Takedaite
Professor Hiroshi Takeda 2007
Formula:
Ca3[BO3]2
Colour:
White to pale grey
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
3.10
Crystal System:
Trigonal
Name:
Named in 1995 in honour of Hiroshi Takeda (武田 弘) (12 September 1934 - 11 September 2023), professor at the Mineralogical Institute, University of Tokyo, Japan, for his contributions to mineralogy. The asteroid (4965) Takeda is also named after him.
This page provides mineralogical data about Takedaite.
Unique Identifiers
Mindat ID:
3872
Long-form identifier:
mindat:1:1:3872:6
IMA Classification of Takedaite
Approved
IMA Formula:
Ca3B2O6
Approval year:
1993
First published:
1995
Classification of Takedaite
6.AA.40
6 : BORATES
A : Monoborates
A : BO3, without additional anions; 1(D).
6 : BORATES
A : Monoborates
A : BO3, without additional anions; 1(D).
24.3.5.1
24 : ANHYDROUS BORATES
3 : AmBn[XO3]p
24 : ANHYDROUS BORATES
3 : AmBn[XO3]p
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 |
|---|---|---|
| Tkd | 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 Takedaite
Vitreous
Transparency:
Translucent
Colour:
White to pale grey
Streak:
White
Hardness:
4½ on Mohs scale
Hardness:
VHN25=429 - 503 kg/mm2 - Vickers
Density:
3.10(2) g/cm3 (Measured) 3.12 g/cm3 (Calculated)
Optical Data of Takedaite
Type:
Uniaxial (-)
RI values:
nω = 1.726 nε = 1.630
Max. Birefringence:
δ = 0.096
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Chemistry of Takedaite
Mindat Formula:
Ca3[BO3]2
Elements listed:
Crystallography of Takedaite
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
R3c
Setting:
R3c
Cell Parameters:
a = 8.638(1) Å, c = 11.850(2) Å
Ratio:
a:c = 1 : 1.372
Unit Cell V:
765.73 ų (Calculated from Unit Cell)
Z:
6
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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2D | Stereo | Red-Blue | Red-Cyan
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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
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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) |
|---|---|---|---|---|---|---|---|
| 0014736 | Takedaite | Schuckmann W (1969) Zur kristallstruktur des calcium-borates Ca3(BO3)2 Neues Jahrbuch fur Mineralogie, Monatshefte 1969 142-144 | 1969 | synthetic | 0 | 293 | |
| 0009534 | Takedaite | Vegas A, Cano F H, Garcia-Blanco S (1975) The crystal structure of calcium orthoborate: a redetermination Acta Crystallographica B31 1416-1419 |  | 1975 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.915 Å | (100) |
| 1.895 Å | (75) |
| 2.756 Å | (61) |
| 2.493 Å | (44) |
| 2.044 Å | (21) |
| 2.160 Å | (19) |
| 1.976 Å | (18) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) |
Type Occurrence of Takedaite
General Appearance of Type Material:
Aggregates of granular crystals up to 0.8 mm long.
Place of Conservation of Type Material:
National Science Museum, Tokyo, Japan; National Museum of Natural History,
Washington, D.C., USA, 165482.
Washington, D.C., USA, 165482.
Geological Setting of Type Material:
A vein of borate minerals along a boundary between crystalline limestone and skarn.
Associated Minerals at Type Locality:
Synonyms of Takedaite
Other Language Names for Takedaite
Common Associates
Associations Based on Photo Data:
| 1 photo of Takedaite associated with Parasibirskite | Ca2(B2O5) · H2O |
| 1 photo of Takedaite associated with Olshanskyite | Ca2[B3O3(OH)6](OH) · 3H2O |
Related Minerals - Strunz-mindat Grouping
| 6.AA.05 | Sassolite | H3BO3 |
| 6.AA.15 | Nordenskiöldine | CaSn4+[BO3]2 |
| 6.AA.15 | Tusionite | Mn2+Sn4+[BO3]2 |
| 6.AA.35 | Jimboite | (Mn2+,Mg)3[BO3]2 |
| 6.AA.35 | Kotoite | Mg3[BO3]2 |
Other Information
Notes:
Easily soluble in dilute hydrochloric acid.
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 Takedaite
mindat.org URL:
https://www.mindat.org/min-3872.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Takedaite
Reference List:
Vegas, A., Cano, F. H., García-Blanco, S. (1975) The crystal structure of calcium orthoborate: a redetermination. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 31 (5) 1416-1419 doi:10.1107/s0567740875005316
Localities for Takedaite
Showing 1 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.
Japan (TL) | |
| Kusachi et al. (1995) +2 other references |
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Fuka mine, Fuka, Bitchū, Takahashi City, Okayama Prefecture, Japan