Sborgite

Sborgite
General
Category	Nesoborates
Formula (repeating unit)	Na[B5O6(OH)4]·3H2O
Strunz classification	6.EA.05
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/c
Identification
Color	colorless
Luster	vitreous
Diaphaneity	transparent

Sborgite is a sodium borate mineral with formula Na[B₅O₆(OH)₄]·3H₂O. The formula can be written as the oxide formulation, Na₂O.5B₂O₃.10H₂O. Sometimes called sodium pentaborate pentahydrate it contains the pentaborate anion, (B₅O₆(OH)₄)⁻.

Sborgite is colorless with monoclinic crystals. It was named for Umberto Sborgi, (1883–1955), Professor of Chemistry, University of Milan, Italy. Sborgite occurs in Tuscany, Italy and the Furnace Creek district, Death Valley, California, US.

See also

• List of minerals

References

• Curzio Cipriani (1957). "Un nuovo minerale fra i prodotti boriferi di Larderello". Atti Rend. Accad. Lincei. 22: 519–525.
• S. Menchetti and C. Sabelli (1978). "The crystal structure of NaB₅O₆(OH)₄". Acta Crystallographica Section B. B34 (1): 45–49. doi:10.1107/S0567740878002289.
• S. Merlino (1972). "The crystal structure of sborgite, NaB5O6(OH)4.3H2O". Acta Crystallographica Section B. B28 (12): 3559–3567. doi:10.1107/S0567740872008349.
• sborgite
• webmineral.com