DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS179

MINERAL_TYPE: Phyllosilicate

MINERAL: Chlorite (Chlorite group)

FORMULA: (Mg,Fe)3(Si,Al)4O10(OH)2-(Mg,Fe)3(OH)6

FORMULA_HTML: (Mg,Fe)₃(Si,Al)₄O₁₀(OH)₂-(Mg,Fe)₃(OH)₆

COLLECTION_LOCALITY: Colorado

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

A spectrum for this sample was published in: Hunt, G.R., J.W. Salisbury, 1970, Visible and near-infrared spectra of minerals and rocks: I. Silicate minerals. Modern Geology, v. 1, p. 283-300.

With the note: "This specimen appears to be quite pure. The spectrum displays three broad bands between 0.7 and 1.1µm. The bands at 0.7µm (barely discernible in this spectrum but very marked in the following sample (HS197) and at 0.9µm are due to Fe3+ in six fold coordination. The band near 1.1µm is due to the ferrous ion in six fold coordination. The sharp features at 1.4µm and between 2.0 and 2.6 µm are hydroxyl bands as in previous samples."

For additional information on spectral features of chlorites see: King, T.V.V. and R.N. Clark, 1989, Spectral Characteristics of Chlorites and Mg-Serpentines Using high-Resolution Reflectance Spectroscopy. Jour. Geophys. Res., 13,997-14,008.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 7.0-9.5 keV
File: chlor179.mdi, *.out
References: Bailey (198-, MSA vol.13, p.557); Huebner's reference patterns
Found: Tri-octahedral mica, trace 7 or 14 angstrom phase, and an unindexed weak reflection at 3.71 angstroms

Comment: The mica could be indexed as a 1M phlogopite; the pattern is very similar to biotite MBLM. Reflections at 7.2 and 3.54 angstroms are consistent with a chlorite or a kaolinite mineral. No 14 angstroms reflection was observed.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Basal cleavage, low relief, slight pleochroism, 1st order gray, biaxial (-), 2V= 10 degrees, twins, all consistent with chlorite. G. Swayze.

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1_2_3_4_

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment

LIB_SPECTRA: splib04a r 949 0.2-2.7µm 200 g.s.= µm

LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=