﻿172 SMITH. 



the hexagonal system and blowpipe tests gave a reaction for phosphorus 

 and no silica. The complete analysis is as follows: 



Analysis of the apatite. 



Per cent. 

 .36 



Fe,0 3 

 A1 2 3 



MgO .71 



■ CaO 54.62 



H,0 at 110° .02 



PA ' 40.95 



F (undetermined) 3.14 



CI Trace. 



Loss on ignition 0.20 



100.00 

 By using the contact goniometer the angle between the faces (0001) 

 and (1011) was found to be a trifle less than 40°. After making the 

 necessary calculations, I found this would give the figures 0.7266 for 

 c, which is a little low, 0.7316 being the usual figures, though there is 

 some fluctuation. 



Such crystallographic data as I could work out on the imperfect ma- 

 terial in our possession are given below. 



Color, lemon yellow on fresh fracture; luster," resinous; fracture, 

 irregular; hardness, 5 to 6; specific gravity, 3.10; system of crystalliza- 

 tion, hexagonal. 



Forms. 



Angles. 



c=(0001) 



cx=42° 



w=(10T0) 





a;=(10Tl) 



as=43° 



a=(1120) 





s=(1121) 



om=60° 





c= .7266 



The finding of apatite in this region associated with the rock pyroxenite 

 is interesting and may lead to highly valuable results when it is recalled 

 that this is the same association obtaining in the apatite deposits of 

 Canada. 



Mica and talc. — In the "Thetford" workings (Ilocos Norte) the most 

 abundant minerals are the micas and the micaceous chlorites and talc. 

 Muscovite, biotite, margarite, phlogopite, pennine and talc were noted, all 

 very mixed in pockets and along shearing planes; much actinolite also 

 accompanied these minerals. Xo large sheets of mica were seen, in fact 

 all these micas occur in rather a triturated condition, so that as I have 

 mentioned above, they could find use only in the industries which employ 

 ground material. It is quite possible, although somewhat improbable, 

 that good sheet mica may be discovered in this region. 



