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Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

(For further information on spectrsocopy, see: http://speclab.cr.usgs.gov)

TITLE: Diopside HS317 (Cr) Pyroxene DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS317

MINERAL_TYPE: Inosilicate

MINERAL: Diopside (Pyroxene group)

FORMULA: CaMgSi2O6

FORMULA_HTML: CaMgSi2O6

COLLECTION_LOCALITY: Finland

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Hedenbergite and with Johannsenite.

"This sample contains both ferrous and ferric iron which produce the absorptions at 0.45, 0.65 and 1.07µm. Ferrous iron substitutes for Mg in diopside. Cr also substitutes for Mg in this sample."

Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1973, Visible and near-infrared spectra of minerals and rocks: VI. Additional silicates. Modern Geology, v. 4, p. 85-106.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Primarily pyroxene; best matches are augite and diopside, but this is not definitive. Small amounts of other phases - pectolite, polyhalite, lazulite are possible contributors to residual.

Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

mode:
94 vol% Diopside
5 vol% Calcite (estimated by fizz in HCl)
1 vol% magnetite (as inclusions in diopside grains)

Very pale green color, some diopside grains white, two cleavages at nearly right angles, inclined extinction, biaxial (+), consistent with diopside. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

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

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 1418 0.2-3.0µm 200 g.s.= 290 µm
LIB_SPECTRA: splib05a r 2415 0.2-3.0µm 200 g.s.=


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