Andesine

Spectrum Details

Modality

NIR

Category

mineral

Material Type

Tectosilicate

Sample ID

HS142.1B, HS142.2B, HS142.3B, HS142.4B

Collection Locality

Montana

Spectral Purity

1c2_3_4_ # HS142.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1c2_3_4_ # HS142.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1c2c3c4c # HS142.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1c2_3_4_ # HS142.4B # 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

Andesine is a plagioclase feldspar series mineral whose end members are albite (Na) and anorthite (Ca). Andesine falls into the 30-50% anorthite category in this series. This sample is a mixture of different phases and was labeled andesine porphyry. The mineral mode confirms this. Average grain size is 40um. This sample could benefit from magnetic separation. The spectrum indicates a weak absorption band near 2.2-2.3 µm, apparently due to trace alteration not detected by other methods. Roger N. Clark Grain size fractions are indicated by the extension after the sample number: .1B = IMAGE_OF_SAMPLE:

XRD Analysis

40 kV - 30 mA, 6.5-9.5 keV File: andes142.mdi, *.out; ands142b.mdi, *.out (smear mount on quartz plate) References: Huebner's reference patterns Found: Plagioclase, K-feldspar, quartz, trace of orthopyroxene Comment: The feldspars were deciphered using patterns for low albite (WAR-0612) and microcline (Felix Chayes' 37A15). All peaks are very sharp indicating a high degree of crystallinity and compositional homogeneity. The two feldspar patterns are distinct. J.S. Huebner, J. Pickrell, T. Schaefer, written communication 1994

X Units

cm⁻¹

Y Units

Absorbance

Data Points

2,126