TITLE: Olivine NMNH137044 Fo92 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH137044

MINERAL_TYPE: Nesosilicate

MINERAL: Olivine (Fosterite-Fayalite series)(Olivine group)

FORMULA: (Mg,Fe)2SiO4 Fo92

FORMULA_HTML: (Mg,Fe)2SiO4 Fo92

COLLECTION_LOCALITY: Chavira Mine, Kamargo (nr), Chihuahau, Mexico

ORIGINAL_DONOR: Smithsonian

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

The sample consists of many 0.5cm particles plus one large fragment. Under petrographic microscope, the hand-picked sample appears clean but one of the grains may be pyroxene.

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

Sample is in two sieve intervals: (a) 74-250µm and (b) <74µm.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Pure forsterite.

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EM(WDS) # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION: SiO2 40.27 wt% SiO2
COMPOSITION: TiO2 0.01 wt% TiO2
COMPOSITION: Al2O3 0.02 wt% Al2O3
COMPOSITION: FeO 8.70 wt% FeO
COMPOSITION: MnO 0.15 wt% Mn0
COMPOSITION: MgO 52.28 wt% MgO
COMPOSITION: CaO 0.06 wt% CaO
COMPOSITION: Na2O 0.02 wt% Na2O
COMPOSITION: K2O 0.01 wt% K2O
COMPOSITION: Total 101.52 wt%

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

Microprobe analysis of hand-picked grains showed the sample to be homogenous within and between grains. Average of 10 analyses showed the sum of the divalent cations too high, but Fo content is approximately 92 mole percent.

Salisbury, J. W., Walter, L. W., and Vergo, N., 1987, Mid-Infrared (2.1-25µm) Spectra of Minerals: First Edition, U.S. Geological Survey Open File Report 87-263.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1_2_3_4_

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment

LIB_SPECTRA: splib04a r 3559 0.2-3.0µm 200 160µm
LIB_SPECTRA: splib04a r 3577 0.2-3.0µm 200 <74µm

LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=