DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS732

MINERAL_TYPE: Tectosilicate

MINERAL: Opal

FORMULA: SiO2*nH2O

FORMULA_HTML: SiO₂•nH₂O

COLLECTION_LOCALITY: Pershing Co., Nevada

ORIGINAL_DONOR: Wards Scientific

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: opal732.out, -.mdi
References: Tada and Iiyama (1983, p. 232); Isaacs et al. (1983, p. 258)
Found: opal having affinity to cristobalite
Quartz sought: no sign of quartz

Comment: 4 broad reflections in positions of strong cristobalite relections. One of these reflections (4.1 angstroms) is extremely intense. Weak, broad reflection at 2.1 angstroms not explained.

J.S. Huebner, J. Pickrell, T. Schaefer, written communication 1994

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1_2_3_4_

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment

LIB_SPECTRA: splib04a r 3745 0.2-3.0µm 200 g.s.=

LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=