Name: Topaz Al2SiO4(F,OH)2
Type: Mineral
Class: Silicate
Subclass: Nesosilicate
Particle Size: Coarse
Sample No.: topaz_3
Owner: JHU
Wavelength Range: TIR
Origin: Durango, Mexico via Don Hoover, USGS
Collection Date: N/A
Description: The sample was composed of several different colorless crystal fragments, each less than a centimeter on a side. Petrographically the sample appeared to be clean and free of obvious fluid inclusions. Particle size was 75 - 250  Micrometers.(Isolated tetrahedra) Original ASTER Spectral Library name was jhu.nicolet.mineral.silicate.nesosilicate.coarse.topaz3.spectrum.txt
Mineral:  Topaz Al2SiO4(F,OH)2

Sample No.:  topaz.3

XRD Analysis:  Topaz plus a small amount of quartz (which does not 
show up in the spectrum).

Chemistry:  Microprobe analysis by Lou Walter and volatile analysis 
by C. S. Papp, J. D. Sharkey, and K. J. Curry, and XRF analysis of the 
non-volatiles by J. Taggare, A. Bartel,  USGS Branch of Analytical 
Chemistry, Denver.  Ten microprobe analyses indicate homogeneity 
within and between grains.  Composition agrees with that of a topaz 
that is F-rich and OH-poor, which is consistent with the intensity of 
the OH bands in the spectrum.  (Note that the spectrum lacks a CO2 
band at 4.3 micrometers typically seen in the more OH-rich samples.  
Because F-rich topaz is orthorhombic and OH-rich triclinic, there are 
also significant differences in the reststrahlen bands between topaz 
samples.)  Average of 10 analyses:

SiO2	36.60
Al2O3	62.30
FeO	0.08
MgO	0.16
CaO	<0.02
K2O	<0.02
Na2O	<0.17
TiO2	<0.02
MnO	<0.02
P2O5	<0.06
H2O	0.09
CO2	<0.01
F	0.38
	_____
Total	99.93

SOLID SAMPLE SPECTRUM  MISSING
