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: Quartz HS117 Aventurine DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS117

MINERAL_TYPE: Tectosilicate

MINERAL: Quartz

FORMULA: SiO2

FORMULA_HTML: SiO₂

COLLECTION_LOCALITY: India

ORIGINAL_DONOR: Hunt and Salisbury collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

"S-18C. Aventurine Quartz. India (117B). Aventurine quartz is a rare variety that has brilliant scales of mica or hematite distributed within it. This particular sample has mica inclusions, as can be seen by comparing the hydroxyl bands near 1.4µ and between 2.2 and 2.6µ with those of muscovite. The very strong band near 0.6µm is not due to the muscovite. We do not know the origin of this band. Some blue quartz which has been analyzed yields Fe₂O₃ (0.5%) and small amounts of TiO₂ as impurities. A band has been observed in some blue Beryl's at 0.62µ, but its origin has been attributed to Fe⁺² in axial channels, and definitely not to Fe⁺² or Fe⁺³ in the Si tetrahedral site."

Sieve interval 74 - 250µm.

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.

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV- 30 mA, 6.5-9.5 keV
File: qtz117.mdi (70 degrees to 16 degrees), qtz117-2.mdi (16 degrees to 5 degrees)
References: Huebner's reference patterns; Borg and Smith (1969); PDF2 #06-0263, 19-0814, 26-0911, 33-1161
Found: Quartz, minor 2M1 dioctahedral mica

Comments: Peaks are sharp; quartz shows excellent resolution of the alpha1-alpha2 components. Profile-based search-match returns quartz and the 2M1 illite as the most likely phases. Of all phlogopite and muscovite patterns in the PDF2 database, only 2M1 muscovites (06-0263, 19-0814) give satisfactory fits. Weak reflections at 5.9 and 5.1 Angstroms were not identified. A very weak peak appears at 7.1 Angstroms in the strip chart but was not resolved in the smoothed digital data.

END_XRD_ANALYSIS.

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

COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # 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 4113	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib05a r 5842	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib06a r 19129			g.s.=