Ulexite
A valid IMA mineral species - grandfathered
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About Ulexite
George L. Ulex
Formula:
NaCa[B5O6(OH)6] · 5H2O
Colour:
Colourless, white, grey with included clays.
Lustre:
Vitreous, Silky
Hardness:
2½
Specific Gravity:
1.955
Crystal System:
Triclinic
Name:
Named after Georg Ludwig Ulex (8 October 1811, Neuhaus, Germany - 25 March 1883, Altona, German Empire), German chemist and politician, who first correctly analyzed the species.
Type Locality:
A rare sodium-calcium borate.
Most specimens of ulexite are fibrous in nature. Most of the time, the fibers are intergrown into felt-like aggregates. Most familiar to collectors is the kind of ulexite that is popularly called "TV rock" because of its natural fiber optic character. Less well known forms are the acicular variety that can make for spectacular specimens and the form that is called "clam shell" ulexite.
Visit gemdat.org for gemological information about Ulexite.
Most specimens of ulexite are fibrous in nature. Most of the time, the fibers are intergrown into felt-like aggregates. Most familiar to collectors is the kind of ulexite that is popularly called "TV rock" because of its natural fiber optic character. Less well known forms are the acicular variety that can make for spectacular specimens and the form that is called "clam shell" ulexite.
Visit gemdat.org for gemological information about Ulexite.Unique Identifiers
Mindat ID:
4085
Long-form identifier:
mindat:1:1:4085:9
Similar Names
IMA Classification of Ulexite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
NaCaB5O6(OH)6·5H2O
Classification of Ulexite
6.EA.25
6 : BORATES
E : Pentaborates
A : Neso-pentaborates
6 : BORATES
E : Pentaborates
A : Neso-pentaborates
26.5.11.1
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
5 : Pentaborates
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
5 : Pentaborates
9.3.21
9 : Borates
3 : Borates of Ca and Sr
9 : Borates
3 : Borates of Ca and Sr
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 |
|---|---|---|
| Ulx | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Ulexite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Ulexite
Vitreous, Silky
Transparency:
Transparent
Colour:
Colourless, white, grey with included clays.
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {010}; on {110} good; on {110} poor.
Perfect on {010}; on {110} good; on {110} poor.
Fracture:
Irregular/Uneven
Comment:
Fracture uneven across fibers.
Density:
1.955 g/cm3 (Measured) 1.955 g/cm3 (Calculated)
Optical Data of Ulexite
Type:
Biaxial (+)
RI values:
nα = 1.491 - 1.496 nβ = 1.504 - 1.506 nγ = 1.519 - 1.52
2V:
Measured: 73° to 78°, Calculated: 68°
Max. Birefringence:
δ = 0.024 - 0.028
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.
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.
Surface Relief:
Moderate
Dispersion:
none
Optical Extinction:
X (11.5°,81°); Y (100°,21.5°); Z (107°,70°) [with c (0°,0°) and b* (0°,90°) using (φ,ρ)].
Chemistry of Ulexite
Mindat Formula:
NaCa[B5O6(OH)6] · 5H2O
Element Weights:
Crystallography of Ulexite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 8.816(3) Å, b = 12.87 Å, c = 6.678(1) Å
α = 90.25°, β = 109.12°, γ = 105.1°
α = 90.25°, β = 109.12°, γ = 105.1°
Ratio:
a:b:c = 0.685 : 1 : 0.519
Unit Cell V:
687.83 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Small nodular, rounded, or lens-like masses; loose at times (termed "cotton balls"), comprised of acicular crystals. Fibers may be radially arranged or randomly oriented towards the centers of the masses and arranged in parallel position at the periphery. Botryoidal crusts or randomly oriented fibers. Compact veins with a parallel fibrous structure. Distinct crystals rare, greatly elongated [001] (Palache et al (1951) Dana's System of Min.: 345).
Twinning:
Polysynthetic, common in massive aggregates and crushed fragments. Several twin laws apply: 1. Polysynthetic on {010} and {100}; 2. {340} or {230} less certain, and others of a more complex nature. The twinning distinguishes ulexite from probertite.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0000611 | Ulexite | Ghose S, Wan C, Clark J R (1978) Ulexite, NaCaB5O6(OH)6*5H2O: Structure refinement, polyanion configuration, hydrogen bonding, and fiber optics American Mineralogist 63 160-171 |  | 1978 | 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 |
|---|---|
| 12.2 Å | (100) |
| 7.75 Å | (80) |
| 6.00 Å | (30) |
| 4.16 Å | (30) |
| 8.03 Å | (15) |
| 4.33 Å | (15) |
| 3.10 Å | (15b) |
Comments:
Jenifer mine, California, USA.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Geological Setting:
Arid regions. In salt playas and desiccated saline lakes.
Type Occurrence of Ulexite
Geological Setting of Type Material:
Playas in a desert region.
Associated Minerals at Type Locality:
Synonyms of Ulexite
Other Language Names for Ulexite
Catalan:Ulexita
Dutch:Ulexiet
Finnish:Uleksiitti
French:Ulexite
German:Ulexit
Boronatrocalcit
Fernsehstein
Franklandit
Hayesit
Natroborocalcit
Natronkalk-borat
Raphit
Stiberit
Tinkalzit
Boronatrocalcit
Fernsehstein
Franklandit
Hayesit
Natroborocalcit
Natronkalk-borat
Raphit
Stiberit
Tinkalzit
Italian:Ulexite
Polish:Uleksyt
Russian:Улексит
Swedish:Ulexit
Turkish:Üleksit
Common Associates
Associations Based on Photo Data:
| 37 photos of Ulexite associated with Kurnakovite | MgB3O3(OH)5 · 5H2O |
| 28 photos of Ulexite associated with Tunellite | SrB6O9(OH)2 · 3H2O |
| 28 photos of Ulexite associated with Calcite | CaCO3 |
| 23 photos of Ulexite associated with Colemanite | Ca[B3O4(OH)3] · H2O |
| 17 photos of Ulexite associated with Realgar | As4S4 |
| 14 photos of Ulexite associated with Inderite | MgB3O3(OH)5 · 5H2O |
| 10 photos of Ulexite associated with Native Arsenic | As |
| 9 photos of Ulexite associated with Probertite | NaCa[B5O7(OH)4] · 3H2O |
| 7 photos of Ulexite associated with Borax | Na2(B4O5)(OH)4 · 8H2O |
| 7 photos of Ulexite associated with Arsenolite | As2O3 |
Related Minerals - Strunz-mindat Grouping
| 6.EA.05 | Sborgite | Na[B5O6(OH)4] · 3H2O |
| 6.EA.05 | Leucostaurite | Pb2[B5O9]Cl · 0.5H2O |
| 6.EA.10 | Ramanite-(Rb) | Rb[B5O6(OH)4] · 2H2O |
| 6.EA.10 | Ramanite-(Cs) | Cs[B5O6(OH)4] · 2H2O |
| 6.EA.10 | Santite | K[B5O6(OH)4] · 2H2O |
| 6.EA.15 | Ammonioborite | (NH4)2[B5O6(OH)4]2 · H2O |
Fluorescence of Ulexite
Yellow, greenish yellow, cream, white.
Other Information
IR Spectrum:
Bulganak volcano material [cm-1]: 3600, 3520, 3420, 3305, 3220, 3125, 1667, 1631, 1470sh, 1413, 1395sh, 1355, 1319, 1211, 1190sh, 1099s, 1058s, 1001s, 980sh, 960sh, 921, 860s, 837, 747, 716, 643, 611, 538, 505sh, 471w, 445
Notes:
Slightly decomposed in cold water and more so in hot water, with the loss of Na to the solution.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Ulexite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Ulexite
mindat.org URL:
https://www.mindat.org/min-4085.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Ulexite
Reference List:
Dana, James D. (1850) A System of Mineralogy (3rd ed.) G. P. Putnam. p.711p.695 - as Hayesine
How, Henry (1857) On the occurrence of natro-boro-calcite with Glauber-salt in the gypsum of Nova Scotia. Silliman's Journal, 230-235As natro-boro-calcite
How, Henry (1877) Contributions to the Mineralogy of Nova Scotia. Mineralogical Magazine and Journal of the Mineralogical Society, 1 (7). 257-260 doi:10.1180/minmag.1877.001.7.11
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.148
Baur, Gretta S., Sand, L. B. (1957) X-ray powder data for ulexite and halotrichite. American Mineralogist, 42 (9-10) 676-678
Baur, G. S., Larsen, W. N., Sand, L. B. (1957) Image projection by fibrous minerals. American Mineralogist, 42 (9-10) 697-699
Allen, Robert D., Almond, Hy (1958) Nonfibrous ulexite from the Kramer District, California. American Mineralogist, 43 (1-2) 169-170
Clark, J. R., Christ, C. L. (1959) Studies of borate minerals (V): Reinvestigation of X-ray crystallography of ulexite and probertite. American Mineralogist, 44 (7-8) 712-719
Weichel-Moore, E. J., Potter, R. J. (1963) Fibre optical properties of ulexite. Nature, 200 (4912) 1163-1165 doi:10.1038/2001163b0
Papezik, V. S., Fong, C. C. K. (1975) Howlite and ulexite from the Carboniferous gypsum and anhydrite beds in western Newfoundland. The Canadian Mineralogist, 13 (4) 370-376
Ghose, Subrata, Wan, Che'ng, Clark, Joan R. (1978) Ulexite, NaCaB5(OH)6·5H2O: structure refinement, polyanion configuration, hydrogen bonding, and fiber optics. American Mineralogist, 63 (1-2) 160-171
Roulston, B. V., Waugh, D. C. E. (1981) A borate mineral assemblage from Penobsquis and Salt Springs evaporite deposits of southern New Brunswick. The Canadian Mineralogist, 19 (2) 291-301
Şener, Savaş, Özbayoǧlu, Gülhan, Demirci, Şahinde (2000) Changes in the structure of ulexite on heating. Thermochimica Acta, 362. 107-112 doi:10.1016/s0040-6031(00)00584-0
Localities for Ulexite
Showing 196 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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Rio Tinto Borax Mine, Kramer Borate deposit, Boron, Kern County, California, USA