lOUfl Certain Mineral Kesources 101 



they have taken place within the space of a few feet. As far 

 as can be ascertained from observations in the field and from the 

 results of mining, the North Carolina mines will average the 

 highest percentage of cut mica of any in the United States. 



There are a number of reasons for this large percentage of 

 waste mica — the irregularity of the blocks of mica and of the 

 individual sheets ; the ruled mica and the "A" mica, which re- 

 duce the sizes of sheets that can be cut or prevent entirely any 

 sheets being cut from the block; the mica m|ay be specked or 

 stained, or may contain a great deal of magnetite in thin crys- 

 tallized films between the foliae of the mica; and many blocks 

 of mica may be destroyed by having garnet, tourmaline, or 

 quartz crystallized out between the foliae. It will be observed 

 from what has been said that in mining mlica there must ne- 

 cessarily be a very large amount of waste rock or gangue re- 

 moved, and, as in nearly all mica mining it is necessary to 

 operate by blasting, it makes the cost of production of the 

 crude mica somewhat expensive. Hence, if any of the other 

 minerals that must be removed in mining can be utilized com- 

 mercially, they will make valuable by-products and will help 

 to pay the cost of mining the mica. 



One of these minerals, feldspar, has already become of 

 commercial importance and is now being produced in ]^orth 

 Carolina. Pure quartz, free from* oxides that would discolor 

 any glass made from it, occurs associated with the mica in 

 many of the deposits, and investigations are now being made 

 to determine the commercial value of this quartz as a source 

 of raw material for the manufacture of glass. 



The production of mica from the Southern States in re- 

 cent years has been principally from jSTorth Carolina with much 

 smaller amounts from Alabama and Virginia. North Caro- 

 lina produces two-thirds of the value of the total production 

 of mica in the United States, 



Other minerals occurring in these pegmatitic dikes which 

 are being mined for mica that will make valuable by-products 

 are kaolin, uranium minerals, samarskite, beryl, and other gem 

 minerals. 



