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Sanbornite with celsian.jpg
Sanbornite (white) with celsian (gray)—Incline, Maricopa County, California
Category Phyllosilicate
(repeating unit)
Strunz classification 9.EF.10
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Pmcn
Unit cell a = 4.62 Å, b = 7.68 Å
c = 13.52 Å; Z = 4
Formula mass 273.50 g/mol
Color Colorless, White
Crystal habit Platy modulated layers
Cleavage Perfect
Mohs scale hardness 5
Luster Vitreous
Streak White
Diaphaneity Transparent to translucent
Specific gravity 3.74
Optical properties Biaxial (-)
Refractive index nα = 1.597, nβ = 1.616, nγ = 1.624
Birefringence δ = 0.0270
Dispersion Weak
References [1][2]

Sanbornite is a rare barium phyllosilicate mineral with formula BaSi2O5. Sanbornite is a colorless to white to pale green, platey orthorhombic mineral with Mohs hardness of 5 and a specific gravity of 3.74.

It was first described from Incline, Mariposa County, California in 1932[3] and named for mineralogist Frank B. Sanborn (1862–1936).

See also[edit]


  1. ^ Sanbornite: Sanbornite mineral information and data
  2. ^ Sanbornite Mineral Data
  3. ^ Rogers, A.F. (1932) Sanbornite, a new barium silicate mineral from Mariposa County, California. Amer. Mineral., 17, 161-172