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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Diopside HS15 Pyroxene DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS15.1B, HS15.2B, HS15.3B, HS15.4B, HS15.8

MINERAL_TYPE: Inosilicate

MINERAL: Diopside (Pyroxene group)

FORMULA: CaMgSi2O6

FORMULA_HTML: CaMgSi2O6

COLLECTION_LOCALITY: Edwards, NY

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 is not a pure magnesian diopside. An absorption bands at 1.05 indicates the presence of ferrous iron in the crystal structure. A small amount of water in fluid inclusions is indicated by the weak H2O absorptions."

Hunt, G.R., J.W. Salisbury, 1970, Visible and near-infrared spectra of minerals and rocks: I. Silicate minerals. Modern Geology, v. 1, p. 283-300.

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
.8 = cut slab

IMAGE_OF_SAMPLE:
Photo of sample

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: diop15.out, -.mdi
References: Borg and Smith (1969); Huebner's reference patterns
Found: Clinopyroxene, trace mica (three basal reflections)

Comment: Superbly crystallized pyroxene. Excellent position and intensity match with synthetic diopside of composition CaMgSi2O6. The high 2-theta side of the -221 reflection has a shoulder that is absent in the pattern of the synthetic material and the pattern calculated by Borg and Smith; however, a similar shoulder is observed in clinopyroxene HS119.3B and in a pattern of diopside from France. The pyroxene is diopside and the mica is probably phlogopite.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

avg. grain size = 295 µm

Pure sample. Large grains 10% surface coated with 10µm diopside grains. Large diopside grains have 8-10 vol% fluid inclusions, inclined extinction, high relief, biaxial (+), two cleavages at nearly right angles, all consistent with diopside. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS15.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS15.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2d3b4b # Diopside HS15.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS15.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1c2_3_4_ # Diopside HS15.8 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns