MINERAL: Apatite-(CaCl) [Chlorapatite]
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.
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J.S. Huebner, J. Pickrell, T. Schaefer, unpublished data, written communication, U.S.G.S., Reston, VA (1994)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):
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem
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)
SPECTRAL_PURITY: 1c2b3b4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns