Tincalconite
A valid IMA mineral species - grandfathered
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About Tincalconite
Formula:
Na2(B4O7) · 5H2O
Colour:
White, colourless (artificial material); colourless in transmitted light.
Lustre:
Vitreous, Dull
Hardness:
2
Specific Gravity:
1.88
Crystal System:
Trigonal
Name:
From "tincal", a Sanskrit name for borax, plus Greek κουία, "konis", powder, alluding to its composition and typical pulverulent occurrence. Pabst and Sawyer (1948) write that the name first appears in 1878 in a list of journal extracts (and attributed to Shepard), but that the original reference is not given and is not known to exist.
Type Locality:
Unique Identifiers
Mindat ID:
3967
Long-form identifier:
mindat:1:1:3967:9
IMA Classification of Tincalconite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Na2B4O5(OH)4·3H2O
Classification of Tincalconite
6.DA.15
6 : BORATES
D : Tetraborates
A : Neso-tetraborates
6 : BORATES
D : Tetraborates
A : Neso-tetraborates
26.4.2.1
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
4 : Tetraborates
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
4 : Tetraborates
9.1.8
9 : Borates
1 : Borates of the alkalis and boric acid
9 : Borates
1 : Borates of the alkalis and boric acid
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 |
|---|---|---|
| Tnc | 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 Tincalconite
Vitreous, Dull
Transparency:
Transparent, Translucent
Colour:
White, colourless (artificial material); colourless in transmitted light.
Streak:
White
Hardness:
2 on Mohs scale
Fracture:
Hackly
Density:
1.88 g/cm3 (Measured) 1.894 g/cm3 (Calculated)
Optical Data of Tincalconite
Type:
Uniaxial (+)
RI values:
nω = 1.461 nε = 1.474
Max. Birefringence:
δ = 0.013
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 (negative)
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 Tincalconite
Mindat Formula:
Na2(B4O7) · 5H2O
Element Weights:
Elements listed:
Crystallography of Tincalconite
Crystal System:
Trigonal
Class (H-M):
32 - Trapezohedral
Space Group:
R32
Cell Parameters:
a = 11.097(2) Å, c = 21.114(4) Å
Ratio:
a:c = 1 : 1.903
Unit Cell V:
2,251.71 ų (Calculated from Unit Cell)
Z:
9
Morphology:
Fine-grained powder. Artificial crystals pseudo-cubic with equal development of the commonest forms "r" and "c," yielding an octahedron-like habit.
Crystal Structure
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CIF File Best | x | y | z | a | b | c
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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) |
|---|---|---|---|---|---|---|---|
| 0002764 | Tincalconite | Luck R L, Wang G (2002) On the nature of tincalconite American Mineralogist 87 350-354 |  | 2002 | 0 | 293 | |
| 0000321 | Tincalconite | Giacovazzo C, Menchetti S, Scordari F (1973) The crystal structure of tincalconite American Mineralogist 58 523-530 | | 1973 | 0 | 293 |
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 |
|---|---|
| 2.92 Å | (100) |
| 4.38 Å | (90) |
| 8.75 Å | (55) |
| 3.44 Å | (55) |
| 2.187 Å | (40) |
| 4.71 Å | (30) |
| 3.00 Å | (30) |
Comments:
Synthetic, ICDD 7-277.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Type Occurrence of Tincalconite
Place of Conservation of Type Material:
No defined type material.
Geological Setting of Type Material:
Metamorphosed bedded borate deposit in clay-shales.
Associated Minerals at Type Locality:
Synonyms of Tincalconite
Other Language Names for Tincalconite
Dutch:Tincalconiet
German:Tincalconit
Juwelierborax
Juwelierborax
Russian:Тинкалконит
Simplified Chinese:三方硼砂
Spanish:Tincalconita
Traditional Chinese:三方硼砂
Common Associates
Associations Based on Photo Data:
| 30 photos of Tincalconite associated with Borax | Na2(B4O5)(OH)4 · 8H2O |
| 6 photos of Tincalconite associated with Hanksite | Na22K(SO4)9(CO3)2Cl |
| 5 photos of Tincalconite associated with Kernite | Na2[B4O6(OH)2] · 3H2O |
| 2 photos of Tincalconite associated with Ezcurrite | Na4B10O17 · 7H2O |
| 2 photos of Tincalconite associated with Inderite | MgB3O3(OH)5 · 5H2O |
| 2 photos of Tincalconite associated with Searlesite | Na(H2BSi2O7) |
| 2 photos of Tincalconite associated with Gypsum | CaSO4 · 2H2O |
| 1 photo of Tincalconite associated with Ulexite | NaCa[B5O6(OH)6] · 5H2O |
| 1 photo of Tincalconite associated with Kurnakovite | MgB3O3(OH)5 · 5H2O |
| 1 photo of Tincalconite associated with Realgar | As4S4 |
Related Minerals - Strunz-mindat Grouping
| 6.DA.10 | Borax | Na2(B4O5)(OH)4 · 8H2O |
| 6.DA.20 | Hungchaoite | Mg(B4O7) · 9H2O |
| 6.DA.25 | Roweite | Ca2Mn2+2B4O7(OH)6 |
| 6.DA.25 | Fedorovskite | Ca2Mg2B4O7(OH)6 |
| 6.DA.30 | Hydrochlorborite | Ca4B8O15Cl2 · 21H2O |
| 6.DA.35 | Uralborite | Ca2[B3O3(OH)5 · OB(OH)3] |
| 6.DA.40 | Numanoite | Ca4Cu(B4O6(OH)6)(CO3)2 |
| 6.DA.40 | Borcarite | Ca4Mg(B4O6(OH)6)(CO3)2 |
| 6.DA.60 | Fontarnauite | (Na,K)2(Sr,Ca)(SO4)[B5O8(OH)] · 2H2O |
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 Tincalconite
mindat.org URL:
https://www.mindat.org/min-3967.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Tincalconite
Reference List:
Localities for Tincalconite
Showing 35 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.
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Boron, Kern County, California, USA