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DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS317.1B, HS317.2B, HS317.3B, HS317.4B, HS317.6
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.
Grain size fractions are indicated by the extension after the sample number:
.1B = <5 µm
.2B = <74 µm
.3B = 74-250 µm
.4B = 250-1200 µm
.6 = cut slab
IMAGE_OF_SAMPLE:
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Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.
Diopside is the major phase with trace amounts of hornblende, quartz, and clay (possibly talc or pyrophyllite). B. Benzel. 2016
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, 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.
Sharp absoprtions a 2.3, 3.5, and 4 microns may indicate the presence of talc or tremolite. G. Swayze
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS317.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS317.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2d3c4c # Diopside HS317.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS317.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS317.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns