sassolite

{{Short description|Mineral form of boric acid}}

{{Infobox mineral

| name = Sassolite

| category = Borate mineral

| boxwidth =

| boxbgcolor =

| image = Sassolite.jpg

| caption = Yellow sassolite

| formula = H₃BO₃

| IMAsymbol = Sso{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| strunz = 6.AA.05

| system = Triclinic

| class = Pinacoidal ({{overline|1}})
(same H-M symbol)

| symmetry = P{{overline|1}}

| unit cell = a = 7.02 Å, b = 7.06 Å
c = 6.59 Å; α = 103.65°
β = 101.11°, γ = 59.98°; Z = 4

| colour = White to gray, may be pale yellow from included sulfur or pale brown from included iron oxides; colourless in transmitted light

| habit = As scaly pseudohexagonal crystals; ncrustations; platy; tabular; may be stalactitic

| twinning = Around [001] as twin axis, common

| cleavage = Perfect on {001}, micaceous

| fracture =

| tenacity = Sectile

| mohs = 1

| lustre = Vitreous to pearly

| refractive = n_α = 1.340 n_β = 1.456 n_γ = 1.459

| opticalprop = Biaxial (−)

| birefringence = δ = 0.119

| pleochroism =

| 2V = Measured: 5°, Calculated: 16°

| streak = White

| gravity = 1.46–1.50

|density=1.46-1.50 g/cm³| melt =

| fusibility =

| diagnostic =

| solubility = Soluble in water

| diaphaneity = Transparent

| other =

| references = [http://rruff.geo.arizona.edu/doclib/hom/sassolite.pdf Handbook of Mineralogy][http://webmineral.com/data/Sassolite.shtml Webmineral.com][http://www.mindat.org/min-3540.html MinDAT]

}}

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.