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Veatchite

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Veatchite
Veatchite-p, Billie Mine, Death Valley, California
General
CategoryPhylloborates
Formula
(repeating unit)
Sr2B11O16(OH)5 · H2O
IMA symbolVea[1]
Strunz classification6.EC.15
Crystal systemMonoclinic
Crystal classDomatic (m)
(same H-M symbol)
Space groupAa
Unit cella = 20.81 Å, b = 11.74 Å
c = 6.63 Å; β = 92.03°; Z = 8
Identification
ColorColorless to white
Crystal habitFlattened platey to prismatic crystals, diverging fibrous clusters and cross fiber veinlets
CleavagePerfect on {010}, indistinct on {001}
Mohs scale hardness2
LusterVitreous to pearly
DiaphaneityTransparent to translucent
Specific gravity2.62
Optical propertiesBiaxial (+)
Refractive indexnα = 1.551 nβ = 1.553 nγ = 1.620
Birefringenceδ = 0.069
2V angleMeasured: 37°
References[2][3][4]

Veatchite is an unusual strontium borate, with the chemical formula Sr2B11O16(OH)5·H2O. There are two known polytypes, veatchite-A and veatchite-p.[5]

Veatchite was discovered in 1938, at the Sterling Borax mine in Tick Canyon, Los Angeles County, California. Veatchite is named to honor John Veatch, the first person to detect boron in the mineral waters of California.

See also

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References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Veatchite on Mindat.org
  3. ^ Veatchite data on Webmineral
  4. ^ Veatchite in the Handbook of Mineralogy
  5. ^ Grice J D, Pring A (2012) Veatchite: structural relationships of the three polytypes, American Mineralogist 97, 489-495
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