Trona
A valid IMA mineral species - grandfathered
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About Trona
Formula:
Na3H(CO3)2 · 2H2O
Colour:
Colourless, gray-white, light yellow; colourless in transmitted light.
Lustre:
Vitreous
Hardness:
2½ - 3
Specific Gravity:
2.11
Crystal System:
Monoclinic
Name:
Trona is a Swedish term, deriving ultimately from the Arabic "natrum", native salt.
A non-marine evaporite mineral. Trona is the primary source of sodium carbonate in the United States.
Chemically similar to wegscheiderite; compare thermonatrite and 'UM1974-04-CO:HNa'.
Chemically similar to wegscheiderite; compare thermonatrite and 'UM1974-04-CO:HNa'.
Unique Identifiers
Mindat ID:
4031
Long-form identifier:
mindat:1:1:4031:6
IMA Classification of Trona
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Na3(HCO3)(CO3)·2H2O
Classification of Trona
5.CB.15
5 : CARBONATES (NITRATES)
C : Carbonates without additional anions, with H2O
B : With large cations (alkali and alkali-earth carbonates)
5 : CARBONATES (NITRATES)
C : Carbonates without additional anions, with H2O
B : With large cations (alkali and alkali-earth carbonates)
13.1.4.1
13 : ACID CARBONATES
1 : Miscellaneous
13 : ACID CARBONATES
1 : Miscellaneous
11.1.6
11 : Carbonates
1 : Carbonates of the alkali metals and ammonium
11 : Carbonates
1 : Carbonates of the alkali metals and ammonium
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 |
|---|---|---|
| Tn | 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 Trona
Vitreous
Transparency:
Translucent
Colour:
Colourless, gray-white, light yellow; colourless in transmitted light.
Streak:
White
Hardness:
2½ - 3 on Mohs scale
Cleavage:
Perfect
On {100} perfect; on {211} and {001} in traces.
On {100} perfect; on {211} and {001} in traces.
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
2.11 g/cm3 (Measured) 2.124 g/cm3 (Calculated)
Optical Data of Trona
Type:
Biaxial (-)
RI values:
nα = 1.412 - 1.417 nβ = 1.492 - 1.494 nγ = 1.540 - 1.543
2V:
Measured: 76° , Calculated: 74°
Max. Birefringence:
δ = 0.126 - 0.128
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:
Moderate (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 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:
relatively strong
Optical Extinction:
X = b; Z ∧ c = 83°.
Chemistry of Trona
Mindat Formula:
Na3H(CO3)2 · 2H2O
Element Weights:
Elements listed:
Chemical Analysis
Oxide wt%:
| 1 | |
|---|---|
| Na2O | 34.10 % |
| CO2 | 23.00 % |
| SO3 | 2.26 % |
| H2O | 39.70 % |
| Total: | 99.06 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Bois-l'Évêque colliery, Laveu, Liège, Liège, Wallonia, Belgium | Analysis by Pisani |
Crystallography of Trona
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 20.4218(9) Å, b = 3.4913(3) Å, c = 10.3326(6) Å
β = 106.452(4)°
β = 106.452(4)°
Ratio:
a:b:c = 5.849 : 1 : 2.96
Unit Cell V:
706.54 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals elongated [010], also flattened {001}. {h0l} faces striated parallel to [010]. Fibrous or massive columnar common.
Comment:
Space Group: I2/a.
Crystallographic forms of Trona
Crystal Atlas:
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Trona no.1 - {100} - Goldschmidt (1913-1926)
Trona no.9 - {001} - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by
www.smorf.nl.
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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) |
|---|---|---|---|---|---|---|---|
| 0009780 | Trona | Choi C S, Mighell A D (1982) Neutron diffraction study of sodium sesquicarbonate dihydrate Acta Crystallographica B38 2874-2876 |  | 1982 | 0 | 293 | |
| 0009779 | Trona | Choi C S, Mighell A D (1982) Neutron diffraction study of sodium sesquicarbonate dihydrate Acta Crystallographica B38 2874-2876 | | 1982 | 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 |
|---|---|
| 2.647 Å | (100) |
| 3.071 Å | (80) |
| 4.892 Å | (55) |
| 9.77 Å | (45) |
| 2.444 Å | (30) |
| 2.254 Å | (30) |
| 2.029 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] |
Geological Setting:
Saline lakes and their evaporites; efflorecences on soils in arid regions.
Synonyms of Trona
Other Language Names for Trona
Common Associates
Associations Based on Photo Data:
| 67 photos of Trona associated with Halite | NaCl |
| 5 photos of Trona associated with Sulphohalite | Na6(SO4)2FCl |
| 5 photos of Trona associated with Nahcolite | NaHCO3 |
| 3 photos of Trona associated with Burkeite | Na6(CO3)(SO4)2 |
| 3 photos of Trona associated with Paralabuntsovite-Mg | Na8K8Mg4Ti16(Si4O12)8(OH,O)16 · 20-24H2O |
| 2 photos of Trona associated with Natron | Na2CO3 · 10H2O |
| 1 photo of Trona associated with Wulfenite | Pb(MoO4) |
| 1 photo of Trona associated with Aegirine | NaFe3+Si2O6 |
| 1 photo of Trona associated with Shomiokite-(Y) | Na3Y[CO3]3 · 3H2O |
| 1 photo of Trona associated with Thénardite | Na2SO4 |
Related Minerals - Strunz-mindat Grouping
| 5.CB. | Piilonenite-(Nd) | NaNd(CO3)2(H2O)3 |
| 5.CB. | Paulišite | Ca2Zn(CO3)3 · 2H2O |
| 5.CB.05 | Thermonatrite | Na2CO3 · H2O |
| 5.CB.10 | Natron | Na2CO3 · 10H2O |
| 5.CB.20 | Monohydrocalcite | CaCO3 · H2O |
| 5.CB.25 | Ikaite | CaCO3 · 6H2O |
| 5.CB.30 | Pirssonite | Na2Ca(CO3)2 · 2H2O |
| 5.CB.35 | Gaylussite | Na2Ca(CO3)2 · 5H2O |
| 5.CB.40 | Chalconatronite | Na2Cu(CO3)2 · 3H2O |
| 5.CB.45 | Baylissite | K2Mg(CO3)2 · 4H2O |
| 5.CB.50 | Tuliokite | Na6BaTh(CO3)6 · 6H2O |
Fluorescence of Trona
May fluoresce under SW UV.
Other Information
Notes:
Soluble in water. Effervesces in acids.
It can exhibit a fiber-optic image transmission effect (Baur et al. 1957).
It can exhibit a fiber-optic image transmission effect (Baur et al. 1957).
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Trona in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Trona
mindat.org URL:
https://www.mindat.org/min-4031.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Trona
Reference List:
Zepharovich, V. v. (1888) Ueber Trona, Idrialin und Hydrozinkit. Zeitschrift für Krystallographie, Mineralogie und Petrographie, 13 (1-6). 135-144 doi:10.1524/zkri.1888.13.1.135
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.146
Walther, P. (1922) Sodium carbonate minerals of the Mogadi Lakes, British East Africa. American Mineralogist, 7 (5) 86-88
Larsen, E.S.; Berman, H. (1934) The microscopic determination of the nonopaque minerals. Bulletin of the US Geological Survey Vol. 848. US Geological Survey p.1-266. doi:10.3133/b848
Murdoch, Joseph (1951) Notes on California Minerals: nuevite=samarskite; trona and hanksite; gaylussite. American Mineralogist, 36 (3-4) 358-361
Baur, G. S., Larsen, W. N., Sand, L. B. (1957) Image projection by fibrous minerals. American Mineralogist, 42 (9-10) 697-699
Pabst, A. (1959) On the hydrates of sodium carbonate, a correction, and the crystallography of trona. American Mineralogist, 44 (3-4) 274-281
Localities for Trona
Showing 170 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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Lake Magadi, Kajiado County, Kenya