56 Pratt — Origin of the Corundum associated with 



been found directly in dunite, it has been observed in serpen- 

 tine, which is the commonest alteration product of dunite. At 

 the Cullakeenee mine, Buck Creek, Clay County, corundum 

 was found that was bordered with serpentine. Some of the 

 specimens observed show the small particles of corundum 

 either entirely or partially surrounded by serpentine and the 

 whole mass of corundum and serpentine surrounded by clino- 

 chlore. In another specimen a streak of corundum about an 

 inch wide lies between two zones of serpentine, from a quar- 

 ter to three quarters of an inch wide, and these in turn are 

 bordered by a talcose and enstatite rock (tig. 4). 



4. 



Fig. 4. Drawn from hand specimen. One-half natural size: a, corundum 

 with a little margarite developed in a few places near the border of the serpen- 

 tine b. The serpentine blends somewhat with the talcose rock c, which on its 

 outer surfaces is composed of enstatite. 



Crystallized corundum has been observed, where the crys- 

 stals, one end of which merge into the massive corundum, pro- 

 ject out beyond the mass, and these projecting portions are 

 often partly or entirely surrounded by chlorite ; while in other 

 cases separate corundum crystals are imbedded in the chlorite. 

 The best crystals of corundum have been found at Corundum 

 Hill, where they occur in the conditions just mentioned. 



Many of the crystals, especially those free from alteration 

 and decomposition, or those only slightly altered, are usually 

 well developed, with smooth even faces and sharp edges. 



In a number of the mines, corundum is found in contact 

 with and surrounded by spinel. At the Carter _ Mine, near 

 Democrat, Buncombe County, the corundum is found in 

 masses of a white and pink color, intergrown with a greenish 



