Name: Orthoclase KAlSi3O8
Type: Mineral
Class: Silicate
Subclass: Tectosilicate
Particle Size: Coarse
Sample No.: orthocl_3
Owner: JHU
Wavelength Range: TIR
Origin: Harris Farm Mica Mine, near Oliver, Goochland Co., Virginiavia the Smithsonian (sample no. NMNH 113188)
Collection Date: N/A
Description: The hand sample is a single 11.97 g fragment of a single crystal.  It is twinned, translucent, light beige in color and appears very pure. Under the microscope, the sample is slightly altered to sericite, otherwise pure. Particle size was 75 - 250 Micrometers.(Framework Silicates); (Feldspar Group) Original ASTER Spectral Library name was jhu.nicolet.mineral.silicate.tectosilicate.coarse.orthoc3.spectrum.txt
Mineral:  Orthoclase KAlSi3O8

Sample No.:  orthocl.3

XRD Analysis:  Pure orthoclase.

Chemistry:  Microprobe analysis indicated typical orthoclase 
composition but there is a slight heterogeneity of the alkalies.  Soda 
varies from 1.5 to 3.5%, while potash varies from 11 to 14%. 
Average of 14 analyses:

SiO2	64.81
TiO2	0.02
Al2O3	19.11
MnO	0.03
K2O	13.51
Na2O	1.69
FeO	0.02
MgO 	0.04
CaO	0.04
	_____
Total	99.34
