DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS69.a, GDS69.b, GDS69.c, GDS69.d, GDS69.e, GDS69.f, GDS69.g
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.
Grain size fractions are indicated by the extension after the sample number:
.a = 150-250 microns
.b = 104-150 microns
.c = 60-104 microns
.d = 30-45 microns
.e = 20-30 microns
.f = 10-20 microns
.g = less than 10 microns
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, EPMA, ICP(Trace), WChem
COMPOSITION_TRACE:
COMPOSITION_DISCUSSION:
None.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Seven grain size intervals were examined:
avg gr sz (µm) | comments | |
150-250microns | 233 | tr quartz |
104-150microns | 171 | lg grains prismatic |
60-104microns | 96 | 5 vol% quartz |
30-45 microns | 55 | 4-5 vol% quartz |
20-30 microns | 40 | 3 vol% quartz |
10-20 microns | 17 | trace quartz |
<10 microns | 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: 1b2b3b4b # Hematite GDS69.a # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4b # Hematite GDS69.b # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4_ # Hematite GDS69.c # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4b # Hematite GDS69.d # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4b # Hematite GDS69.e # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3b4b # Hematite GDS69.f # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2d3c4c # Hematite GDS69.g # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns