Mineral:  Topaz Al2SiO4(F,OH)2

Sample No.:  topaz.4

XRD Analysis:  Pure topaz.

Chemistry:  Microprobe analysis by Lou Walter and volatile analysis 
by C. S. Papp, J. D. Sharkey, and K. J. Curry, USGS Branch of Analytical 
Chemistry, Denver.  Ten microprobe analyses indicate homogeneity 
within and between grains.  The composition agrees with that of a 
topaz:

SiO2	36.4
Al2O3	62.2
FeO	<0.04
MgO	0.12
CaO	<0.02
K2O	<0.02
Na2O	<0.17
TiO2	<0.02
MnO	<0.02
P2O5	<0.06
H2O	0.30
CO2	<0.01
F	0.47
	_____
Total	99.85

SOLID SAMPLE SPECTRUM MISSING
