Genth, 



386 



[Sep. 19, 



to be damourite. The pseudo morphous crystals show the shape of the 

 corundum but are flattened as if by exposure to a heavy pressure. Many 

 still contain a nucleus of unaltered corundum, others are entirely changed. 

 They are aggregates of small yellowish-white scales. The material, 

 which I have analyzed, was first purified by dilute chlorhydric acid and 

 then presented the appearance of silver-white scales (g). 



h. Very similar is the damourite which forms a bed of mica schist at 

 the Cnlsagee Mine. The scales are somewhat larger than those from 

 South Carolina, and the corundum crystals which still exist in it, not 

 quite as deeply altered. They are associated with small grains of massive 

 staurolite and some other black minerals, probably menaccanite, etc. An 

 analysis of the scales purified by chlorhydric acid was made by Dr. 

 Koenig, the results of which is given below (/<). 



%. The damourite, investing the crystals and masses of blue corundum 

 at Crowder's Mountain and resulting from its alteration, occurs in scales, 

 which are generally coated with ferric hydrate. A sample purified by 

 chlorhydric acid was analyzed by Mr. Thos. M. Chatard (see below, i). 



The results of the analyses of the various varieties of damourite, are 

 as follows : 



Spec. Gr. 



Si0 2 



A1A 



Fe 2 : , 



MgO 



CaO 



Li 2 



Na 2 



K 2 



Ignition 



Spec 

 SiO., 

 A1 2 3 



Fe 2 3 



MgO 



CaO 



Li 2 



Na 2 



K 2 



Ignition 



Gr. 



100.44 99.28 99.99 



* Mean of three determinations. 



99.86 



102.21 



