Sample Description USGS Spectral Library Version 7

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
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TITLE: ClinozoisiteEpidote HS299 DESCRIPT

DOCUMENTATION_FORMAT: MIXTURE

SAMPLE_ID: HS299.1B, HS299.2B, HS299.4B, HS299.6

MIXTURE_TYPE: Intimate

MIXTURE: Clinozoisite (Epidote group) and Epidote

FORMULA: Ca2Al3(SiO4)3(OH) and Ca2(Al,Fe+3)3(SiO4)3(OH)

FORMULA_HTML: Ca₂Al₃(SiO₄)₃(OH) and Ca₂(Al,Fe⁺³)₃(SiO₄)₃(OH)

COLLECTION_LOCALITY: Mexico

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Clinozoisite is dimorphous with Zoisite.

"This sample forms a continuous series with epidote. The sample contains some epidote and quartz impurities. The sample probably contains some Mn³⁺ and Fe³⁺ substituting for its aluminium, which would explain its reddish-brown color. The presence of these ions would also explain absorption features at 0.41, 0.46, 0.55, and 0.8 µm. Absorption features attributed to the hydroxyl and water appear at longer wavelengths than normal."

Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1973, Visible and Near-Infrared Spectra of Minerals and Rocks: VI. Additional Silicates. Mod. Geol. 4, pp 85-106.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 7.0-9.5 keV
File: clzst299_mdi, *.out (smear mount on quartz plate)
References: Borg and Smith (1969); Huebner's reference patterns
Found: monoclinic zoisite, subordinate quartz
Sought but not found: zoisite

Comment: Monoclinic zoisites have similar patterns. Grains are white (quartz), pink and yellow. Based on macroscopic color, eliminate epidote (green) and piemontite (red). Conclude HS-299 from a color-zoned clinozoisite crystal, but the origin of the colors is unknown. Reflections are very sharp, indicating excellent crystallinity.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

mode:
85-90 vol% clinozoisite
10-15 vol% epidote
tr? qtz
tr opaques

Clinozoisite, 2V=60 degrees, anomalous blue color, pink in transmitted light, many grains lie on cleavages giving close to optic axis figures, grains too small for sign determination, unclear whether this is epidote or clinozoisite, although green grains are probably epidote and pink grains clinozoisite. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # HS299.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3c4_ # HS299.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # HS299.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # HS299.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns