INFRA-RED REFLECTION SPECTRA. 



was ground parallel to the needles. The reflection curve is of the usual 

 form and shows maxima at 9.4, 10.3, and 10.8/1. 



40% 



c 

 o 

 '-p 

 o 



<a 

 ir 



>o 



e 9 /o 

 FIG. 78. Glass (a); Pectolite. 



WILLEMITE (Zn 2 SiO). 

 (Curve a, fig. 79.) 



The reflecting surface was ground from a massive specimen. The 

 transmission curve becomes opaque very abruptly at 9 fi. This is fol- 

 lowed by a sudden rise in the reflection curve at IO/A. There are three 

 strong maxima at 10.1, 10.6, and n /A, respectively, followed by a small 

 band at n.6p.. From the location of the maxima it is evident that the 

 bonding of the SiO 2 in willemite is different from that of quartz. 



56 7 8 9 /O 



FIG. 79. Willemite (a) ; Vaiicite. 



VARICITE 



(Curve b, fig. 79.) 



The reflecting power is low, and decreases uniformly from 4 to 7.5 p., 

 where it decreases abruptly to 8.5 p.. There are maxima at 9.25 and 



