Bruneau Jasper

A particularly attractive picture jasper from Bruneau River Canyon in Owyhee County, Idaho, USA.

The deposit was near the bottom of the canyon walls, where the jasper-bearing rhyolite lies exposed for about 8km.

Production of Bruneau Jasper stopped in 2009.
^{Source: Wikipedia}

Formula:

SiO₂

Crystal system:

trigonal

Mohs hardness:

6.5-7

Specific gravity:

2.58-2.91

Refractive index:

birefringent 1.543-1.554

Max. Birefringence:

0.009

Dispersion:

none

Pleochroism:

none

Luminiscence:

inert

Lustre:

waxy

Cleavage:

none

Fracture:

conchoidal,splintery

Colour:

brown, reddish brown, cream