430 



J. H. Pratt — Mineralogical Notes. 



more fibrous and not of such good quality as that from near 

 Bakersville. 



I (Baskerville). II (Penfleld). 



Si0 2 56-40 57*98 



A1 2 3 1-15 -63 



FeO J 1-40 10-39 



MuO .... -31 



MgO 28-68 28-69 



CaO -50 -20 



H 2 _ 1-63 1-67 



Loss at 100°... -12 



99-76 



99-99 



Enstatite. — The enstatite from Corundum Hill, that is com- 

 monly called anthophyllite, occurs as a rock composed of a 

 mass of interlocking bladed grayish crystals. The rock is 

 very tough and tenacious and forms a perfectly continuous 

 mass with the dunite, which is exposed over nearly the entire 

 surface of the hill. 



The analysis of this mineral by Dr. Baskerville* is as fol- 

 lows : 



Si0 2 51-64 



A1 0,.-. -. -12 



FeO.. 9-28 



MnO -56 



MgO 31-93 



CaO -45 



H 2 5-45 



Ratio. 

 861 

 001 

 129^1 

 008 I 

 798 f 

 008 J 

 303 



•943 



99-43 



It is evident from the amount of H 2 found that the mate- 

 rial analyzed was impure, and as shown by the calculations 

 below, the ratio in the above analysis corresponds to a mixture 

 of 44*5 per cent enstatite, 35 per cent serpentine and 205 per 

 cent talc. The analysis is also given below after substituting 

 for MnO and CaO their equivalent of MgO, deducting Al 2 O s 

 and recalculating to 100 per cent. 



44*5 per cent. 

 Enstatite. 



Si0 2 24-42 



FeO 7-58 



MgO 12-50 



H 2 0.._. _-._ 



Ratio. 

 •407 

 •105 

 •312 



35 per cent. 

 Serpentine. 



14-87 



1-84 

 13-83 



4-46 



Ratio 



•246 



■025 



•346 



•246 



20"5 per cent. 

 Talc. 



13-02 



651 



■97 



Ratio. 

 •217 



•163 

 •054 



Total 

 5231 



9 42 

 32-84 



5-43 



Recalculated 

 Analysis. 



52-19 

 9-39 



32-91 

 5-51 



44-50 35-00 20-50 



*N. C. Geological Survey, Bull. 11, p. 27. 



100-00 100-00 



