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: Jarosite GDS24 Na DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: GDS24

MINERAL_TYPE: Sulfate

MINERAL: Natro-Jarosite (Alunite group)

FORMULA: (Na)(Fe+3)3(SO4)2(OH)6

FORMULA_HTML: (Na)Fe₃⁺³(SO₄)₂(OH)₆

COLLECTION_LOCALITY: MIT Mineral Collection, Dave Sherman

ORIGINAL_DONOR: MIT Mineral Collection, Dave Sherman

CURRENT_SAMPLE_LOCATION: USGS Denver, Dave Sherman

ULTIMATE_SAMPLE_LOCATION: USGS Denver, Dave Sherman

SAMPLE_DESCRIPTION:

The spectrum looks like a beautiful jarosite spectrum with no contaminants. Roger N. Clark

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Jarosite - major.
Unidentified residual in appreciable amounts; note peaks at 5.58, 5.5542, 2.769.
Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.

40 kV - 30mA, 7.3-9.5 keV
File: najar24.mdi
References: JCPDS # 36-425; Huebner's reference patterns
Found: a jarosite mineral

Comment: Peaks are very narrow and the resolution of the alpha1-alpha2 reflections is good, indicating that GDS-24 is well crystallized and compositionally homogeneous. The relative peak intensities do not match those of the JCPDS pattern or Huebner's reference patterns (see also GDS-100, -101). The value of the c cell dimension, based on the (003), (006), amd (009) reflections, is significantly smaller than that of synthetic Na-jarosite.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

Na-jarosite. .

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Rhombohedral plates, moderate relief, straight extinction? Grains too small - may be length slow. All consistent with alunite (hydronium jarosite is part of Alunite Group) except for length slow? G. Swayze

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4b # 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 2467	0.2-3.0µm	200	g.s.= 15 µm
LIB_SPECTRA:	splib05a r 3648	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib06a r 11320			g.s.=
LIB_SPECTRA:	splib06a r 11332			g.s.=