Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

(For further information on spectroscopy, see: http://speclab.cr.usgs.gov)

TITLE: Chlorapatite WS423 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: WS423

MINERAL_TYPE: Phosphate

MINERAL: Chlorapatite (Apatite group)

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:

Spectrum shows weak Nd⁺³ bands.

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J.S. Huebner, J. Pickrell, T. Schaefer, unpublished data, written communication, U.S.G.S., Reston, VA (1994)

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

LIB_SPECTRA_HED:	where	Wave Range	Av_Rs_Pwr	Comment
LIB_SPECTRA:	splib04a r 938	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib05a r 1650	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib06a r 4636			g.s.=
LIB_SPECTRA:	splib06a r 4648			g.s.=