TITLE: Halloysite NMNH106237 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH106237

MINERAL_TYPE: Phyllosilicate

MINERAL: Halloysite (Kaolinite-Serpentine group)

FORMULA: Al2Si2O5(OH)4

FORMULA_HTML: Al2Si2O5(OH)4

COLLECTION_LOCALITY: Indiana

ORIGINAL_DONOR: National Museum of Natural History

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Polymorphous with Dickite, Kaolinite, and Nacrite.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

7A halloysite - does not expand with glycol. Pure. (Norma Vergo)

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE:

None

COMPOSITION_DISCUSSION:

None

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

av gr sz = 300 µm

Grains about 90 vol% isotropic under cross-polarized light, and have variations in transparency suggesting inclusion of opaque materials up to 10 vol%. All this is consistent with halloysite slightly contaminated by other clays & opaques. Large grains 10% coated with smaller grains. 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 1930 0.2-3.0µm 200 g.s.= 300 µm

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

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