MINERAL: Jarosite (K-Jarosite) (Synthetic) (Alunite group)
ORIGINAL_DONOR: Roger Stroffregen, SMU
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
Sample synthesized at 90C
40 kV - 30 mA, 7.3-6.5 keV
Reference: JCPDS #22-827 (jarosite)
Comment: Sharp patterns (GDS99 is exceptional) indicate good crystallinity and compositional homogeneity. All reflections are accounted for by the JCPDS card. However, the samples are not identical. GDS98 has cell hexagonal dimensions a = 7.313(1) and c = 17.060(4) Angstroms whereas GDS99 has a = 7.302(1) and c = 17.214(2) Angstroms. The difference in c is significant and suggests a composition difference between the two samples. Are there differences in the optical spectra?"
J.S. Huebner, J. Pickrell, and J. Randow, 1993, written communication.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem
There is a slight longward shift to the 2.26 micron absorption in the Beckman spectrum relative to the more accurate position of this same band in the Nicolet FTIR data. The other bands in the Beckman spectrum appear to match those of the nicolet data better.
SPECTRAL_PURITY: 1a2a3a4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns