Desert Varnish

Spectrum Details

Modality

NIR

Category

coating

Material Type

Coating

Sample ID

ANO90-14

Collection Locality

Arches National Park

Spectral Purity

1a2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Composition / XRD

None # XRF, EPMA, ICP(Trace), WChem

Sample Description

"Desert varnish invariably consists of birnessite in intimate mixture with hematite and large amounts of clay minerals. The clays are generally of the illite-montmorillonite type with minor kaolinite, but in several samples this concentration ratio is reversed." Potter, R.M. and G.R. Rossman, 1979, Mineralogy of manganese dendrites and coatings. American Mineralogist, v.64, pp 1219-1226. This sample is a coating on sandstone.

X Units

cm⁻¹

Y Units

Absorbance

Data Points

2,126