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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Bronzite HS9 Pyroxene DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS9
MINERAL_TYPE: Inosilicate
MINERAL: Bronzite (ferroan Enstatite) (Pyroxene group)
FORMULA: (Mg,Fe+2)2Si2O6
FORMULA_HTML: (Mg,Fe+2)2Si2O6
COLLECTION_LOCALITY: Jackson Co., North Carolina
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Spectrum displays double ferrous iron band typical of iron-rich orthopyroxenes.
Original spectrum published in:
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.
"S-17E. Pyroxene, variety Bronzite. Jackson CO, N. Carolina (9B). This sample also displays the double ferrous ion band in the near-infrared typical of iron-rich orthopyroxenes. The slight band in the visible at 0.5µm is also a ferrous ion band."
Sieve interval 74 - 250µm.
Weak absorptions at 1.4 and 2.3 µm indicate trace alteration/contamination (probably tremolite). Roger N. Clark
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA, 6.5-9.5 keV
File: brnzt9.out, -.mdi; brnzt9b.out, -.mdi (at low angles)
(Both patterns obtained from smear mounts on quartz plates)
References: Huebner's reference patterns
Found: orthopyroxene, minor talc, trace chlorite (?), many un indexed moderately
to very weak reflections (6.35, 5.25, 3.90, 3.58, 3.27, 3.23, 2.775, 2.255,
1.888, 1.643, and 1.580 angstroms)
Comment: Sharp, strong pattern of orthopyroxene. Talc based on four basal
reflections. Needs more work.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
85 vol% Bronzite
10 vol% quartz (uniaxial +)
5 vol% green grains (augite?) and Fe-stained pyroxene
avg. grain size = 260 µm
Prismatic grains, two cleavages at near 90 degree angle, straight extinction, length slow, high relief, all consistent with orthopyroxene. Opaque inclusions in bronzite (< 1vol%). 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 711 | 0.2-3.0µm | 200 | g.s.= 260 µm |
| LIB_SPECTRA: | splib05a r 1381 | 0.2-3.0µm | 200 | g.s.= |
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