Sassolite

Sassolite
Yellow sassolite
General
CategoryBorate mineral
Formula
(repeating unit)
H3BO3
IMA symbolSso[1]
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
LustreVitreous 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[2][3][4]

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.[2]

  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. ^ a b Handbook of Mineralogy
  3. ^ Webmineral.com
  4. ^ MinDAT