TITLE: Hematite GDS69 DESCRIPT

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_TRACE:

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.=