82 



INFRA-RED REFLECTION SPECTRA. 



The reflection is complex, with maxima at 6.6 and 6.85 p,. Aschkinass 1 

 found a band at 6.69 p. for Iceland spar, while his curve for marble is 

 flat, and evidently complex. 



MAGNESITE (MgCO 3 ). 

 (Massive. Curve b, fig. 66.) 



The band of selective reflection is similar to that of calcite, and con- 

 sists of two maxima at 6.5 and 6.8 p., respectively. 



60 <% 



50 



V 



it- 

 CD 

 CE 



20 



10 



\ 



6739 

 FIG. 67. Microcline (a) ; Talc. 



IO 



II 



MICROCLINE (KAlSiaOs). 

 (Cleavage piece parallel to c; polished. Curve a, fig. 67.) 



The reflection band from 9 to IO/A is complex. There are sharp 

 maxima at 8.85 and 9.95 p., with a probable band at n /*. 



TALC 



(Massive. Curve b, fig. 67.) 



There are sharp maxima at 9.05 and 9.75 /*. Beyond this point to 

 12 p. there is great transparency. 



* Aschkinass, loc. cit. 



