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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Hematite GDS69 DESCRIPT

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

IMAGE_OF_SAMPLE:
Photo of sample

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