Sborgite

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
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 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. 

This article uses material from the Wikipedia article  Metasyntactic variable, which is released under the  Creative Commons Attribution-ShareAlike 3.0 Unported License.