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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: Chlorapatite WS423 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS423

MINERAL_TYPE: Phosphate

MINERAL: Apatite-(CaCl) [Chlorapatite]

FORMULA: Ca5(PO4)3Cl

FORMULA_HTML: Ca5(PO4)3Cl

COLLECTION_LOCALITY: Snarum, Norway

ORIGINAL_DONOR: Wards Scientific

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION: Single large brown crystal with indistict cleavage.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV

Reference: JCPDS #33-271 (synthetic chlorapatite); Hughes and others (1989)

Found: Apatite plus un indexed weak reflections at 26.61 [near position of the strongest quartz reflection, the (101)] and at 25.94, 31.71, 32.84, and 43.4 degrees 2 theta.

Cell dimensions: a=9.6078(8), c=6.7912(8) Angstroms, using BaF2 internal standard

Comment: an apatite, probably Cl-rich, plus at least one, and probably two, minor additional phases. Extraordinarily clear pattern with many sharp peaks indicating high degree of crystallinity and compositional homogeneity. Synthetic chlorapatite is reported to have a=9.641 and c=6.771 Angstroms; natural chlorapatite with F.09Cl.88 has a=9.598, c=6.776 Angstroms. Although the cell dimensions of WS416 appear similar to those of the analyzed natural fluorapatite, the cell dimensions of the reference synthetic and natural fluorapatites do not agree. Thus, there is uncertainty in the composition of WS416.

J.S. Huebner, J. Pickrell, T. Schaefer, unpublished data, written communication, U.S.G.S., Reston, VA (1994)

additional XRD analysis (B. Benzel):

Chloroapatite (96%)
Hydroxyapatite (4%)

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION: Sample has a number of sharp relatively weak spectral absorptions (f-f orbital electronic transitions) throughout the 0.35 to 1.0 micron range presumably due to variable proportions of lanthanide series rare earth elements (i.e., Nd, Sm, and others). Bands at 0.585, 0.748, 0.804, and 0.872 microns resemble similar absorptions in neodymium oxide. (G. Swayze)

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1c2b3b4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns