DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS69
MINERAL_TYPE: Oxide
MINERAL: Hematite (Hematite group)
FORMULA: alpha-Fe2O3
FORMULA_HTML: alpha-Fe2O3
COLLECTION_LOCALITY: Republic, Michigan
ORIGINAL_DONOR: Wards Natural Science Inc.
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Dimorphous with Maghemite.
This sample was wet sieved to the following grain size intervals for a study on grain size effects by Roger Clark. The sample was a single rock of specular hematite that appeared pure.
>250µm
150-250µm (a)
104-150µm (b)
60-104µm (c)
45-60 µm
30-45 µm (d)
20-30 µm (e)
10-20 µm (f)
<30 µm
<10 µm (g)
Letter denotes spectrum designation. Those without a letter were not measured. END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Comments: Using the quartz (101) and the anomalously intense (211) reflections as an internal standard for 2 theta, eleven hematite reflections were refined to obtain the cell dimensions a=5.035(1) and b0=13.750(4). Within the limits of error given above (1 sigma), these dimensions are those of pure Fe2O3 (see PDF2 33-0664).
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_DISCUSSION:
None.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Seven grain size intervals were examined:
| avg gr sz (µm) | comments | |
| 150-250µm | 233 | tr quartz |
| 104-150µm | 171 | lg grains prismatic |
| 60-104µm | 96 | 5 vol% quartz |
| 30-45 µm | 55 | 4-5 vol% quartz |
| 20-30 µm | 40 | 3 vol% quartz |
| 10-20 µm | 17 | trace quartz |
| <10 µm | 10.5 | trace quartz |
Anhedrally fractured grains, mostly specular, but occasionally massive surfaces. Some grains slightly attracted to magnet. Red color diagnostic of hematite. G. Swayze.
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 2036 0.2-3.0µm 200 g.s.= 233µm
LIB_SPECTRA: splib04a r 2047 0.2-3.0µm 200 g.s.= 171µm
LIB_SPECTRA: splib04a r 2058 0.2-3.0µm 200 g.s.= 96µm
LIB_SPECTRA: splib04a r 2069 0.2-3.0µm 200 g.s.= 55µm
LIB_SPECTRA: splib04a r 2080 0.2-3.0µm 200 g.s.= 40µm
LIB_SPECTRA: splib04a r 2091 0.2-3.0µm 200 g.s.= 17µm
LIB_SPECTRA: splib04a r 2103 0.2-3.0µm 200 g.s.= 10.5µm
LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=
LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=