Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

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

TITLE: Diopside HS15 Pyroxene DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS15

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.

IMAGE_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, EM(WDS), 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: 1c2d3b4b # 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 1429	0.2-3.0µm	200	g.s.= 295 µm
LIB_SPECTRA:	splib05a r 2404	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib06a r 6924			g.s.=
LIB_SPECTRA:	splib06a r 6935			g.s.=