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(For further information on spectrsocopy, see:
http://speclab.cr.usgs.gov)
TITLE: Copiapite GDS21 DESCRIPT
DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS21
MINERAL_TYPE: Sulfate
MINERAL: Copiapite (Copiapite group)
FORMULA: Fe+2(Fe+3)4(SO4)6(OH)2*20H2O
FORMULA_HTML: Fe+2Fe+34(SO4)6(OH)2•20H2O
COLLECTION_LOCALITY: Cyprus
ORIGINAL_DONOR: MIT Mineral Collection, Dave Sherman
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 (smear mount on quartz, copiapit.out);
40 kV - 30 mA, 7.3-9.5 keV (slurry onto quartz plate, copiapt2.out)
References: JCPDS #35-583, 29-714, 20-659, 19-394, 33-1472, 42-599,
27-77
Found: two members of the copiapite group; perhaps at least one
additional phase
Comment: The original pattern (copiapit.out) was barren above 30 degrees;
a second pattern showed little above 38 degrees but the strip chart
revealed that some reflections at low 2 theta are doublets,
indicating the presence of two phases having related structures.
The intensity ratio is about 5:2. There are seven mineral
species in the copiapite group. I have not succeeded in
completely indexing the pattern, using the JCPDS data, so I
don't know which copiapite species (or solid solutions) are
present. EDA analysis (on the SEM) shows a aluminum and
silicon in addition Fe, S, and O. This results could indicate
that one of the copiapites is Al-rich. Also that a trace of
quartz is present (there are what I call insignificant peaks at
the positions of the strong quartz (100) and (101) reflections -
insignificant because they could just as likely be background
noise. A hand-specimen with crystals suitable for single-
crystal X-ray diffraction would help us sort out the copiapite
species present."
J.S. Huebner, J. Pickrell, and T. Schaefer, 1994, written communication.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Yellow color, good rhombic(?) cleavage, inclined extinction, length fast, unable to get good interference figure because of preferred cleavage orientations. Trace pink transparent mineral. G. Swayze.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2_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 1239 | 0.2-3.0µm | 200 | g.s.= 225 µm |
| LIB_SPECTRA: | splib05a r 2201 | 0.2-3.0µm | 200 | g.s.= |
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