Chemistry:Sassolite

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Short description: Mineral form of boric acid
Sassolite
Sassolite.jpg
Yellow sassolite
General
CategoryBorate mineral
Formula
(repeating unit)
H3BO3
Strunz classification6.AA.05
Crystal systemTriclinic
Crystal classPinacoidal (1)
(same H-M symbol)
Space groupP1
Unit cella = 7.02 Å, b = 7.06 Å
c = 6.59 Å; α = 103.65°
β = 101.11°, γ = 59.98°; Z = 4
Identification
ColourWhite to gray, may be pale yellow from included sulfur or pale brown from included iron oxides; colourless in transmitted light
Crystal habitAs scaly pseudohexagonal crystals; ncrustations; platy; tabular; may be stalactitic
TwinningAround [001] as twin axis, common
CleavagePerfect on {001}, micaceous
TenacitySectile
Mohs scale hardness1
Vitreous to pearly|re|er}}Vitreous to pearly
StreakWhite
DiaphaneityTransparent
Specific gravity1.46–1.50
Optical propertiesBiaxial (−)
Refractive indexnα = 1.340 nβ = 1.456 nγ = 1.459
Birefringenceδ = 0.119
2V angleMeasured: 5°, Calculated: 16°
SolubilitySoluble in water
References[1][2][3]

Sassolite is a borate mineral, specifically the mineral form of boric acid. It is usually white to gray, and colourless in transmitted light. It can also take on a yellow colour from sulfur impurities, or brown from iron oxides.[1]

History and occurrence

Its mineral form was first described in 1800, and was named after Sasso Pisano, Castelnuovo Val di Cecina, Pisa Province, Tuscany, Italy where it was found.[3] The mineral may be found in lagoons throughout Tuscany and Sasso.[2] It is also found in the Lipari Islands and the US state of Nevada. It occurs in volcanic fumaroles and hot springs, deposited from steam, as well as in bedded sedimentary evaporite deposits.[1]

See also

References

  1. 1.0 1.1 1.2 Handbook of Mineralogy
  2. 2.0 2.1 Webmineral.com
  3. 3.0 3.1 MinDAT
  4. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode2021MinM...85..291W. 

External links