364 JOSEPH HYDE PRATT 



against which the layer of scrap mica is kept tightly in place 

 by means of heavy canvas. A number of the states, especially 

 North Carolina, offer very favorable locations for the erection 

 of plants to manufacture products from scrap mica, as there 

 is usually a supply of available water power near the deposits. 

 The commercial value of scrap mica before it is ground 

 is from $8 to $10 per ton, delivered at the railroad, and it is 

 this value that has made it possible to work some of the mines 

 that otherwise would have been shut down, for in some cases 

 this waste mica represents from 75 to 95 per cent of the mica 

 mined. After being ground, the mica is worth from $40 to 

 $60 per ton, according to its mesh. 



There are a number of minerals, especially quartz and 

 fieldspar, associated with the mica, which in some instances 

 should prove of considerable commercial value as by-products 

 in mining the mica, provided water power for grinding these 

 minerals can be secured near the source of supply. Occasion- 

 ally some of the gem minerals, as beryl and tourmaline, are 

 found associated with the mica, and furnish some very hand- 

 some cut stones. Some of these pegmatitic mica bearing 

 dikes are rich in the variety of minerals that they contain, 

 while others have very few besides these typical of a pegma- 

 titic dike. Between forty five and fifty different minerals 

 have been found associated with mica at the different mines 

 throughout the country. 



The small production of mica in the United States as 

 compared with the importation is not due to a deficiency in 

 the supply of the mineral in this country. It is undoubtedly 

 true that in the Appalachian region, especially in the southern 

 area, there are many good deposits of mica yet to be discovered 

 which will yield as rich returns as many of those that have 

 already been mined. It is also true that many of the mines 

 that were worked so extensively twenty years ago, especially 

 those in North Carolina, still contain good deposits of mica 

 which the former owners were prevented from taking out on 

 account of the presence of water, which they were unable to 

 control with the means that they had at hand. Any increase 

 in the duty on mica or any considerable decrease in the im- 



