156 



NEW YORK STATE MUSEUM 



or part of their year's product to local middlemen who sometimes 

 work quarries of their own. In the last decade the average pro- 

 duction has been less than $20,000, although in earlier years it often 

 exceeded $100,000. The statistics herewith include the output of 

 chasers as well as millstones. 



Production of millstones since 1904 



1904 



1905 

 1906 

 1907 

 1908 

 1909 

 1910 

 1911 



1912 $15 358 



1913 13 130 



1914 12 410 



1915 10 916 



1916 10 287 



1917 22 103 



1918 25 488 



References 

 Mather, W. W. Geology of New York. Report on First District, 1843, p. 357 

 Nason, F. L. Economic Geology of Ulster County. N. Y. State Mus. 47th 

 Ann. Rep't, 1894 



MINERAL PAINTS 



Natural mineral pigments are referred to here, such as are made 

 by the physical preparation of an ore or mineral aggregate. They 

 constitute only a part of the products of the paint industry in general 

 prepared from mineral bases, as the more important branch is that 

 of manufacturing lead pigments. These require elaborate chemical 

 operations upon which depends the particular coloring quality of 

 the pigments, and all the metallic lead thus used is derived from 

 sources outside of the State. In making the natural pigments, on 

 the other hand, the mineral materials are simply washed or ground 

 to secure the desired degree of fineness, with a resort to calcination 

 in some cases to improve the color. 



The raw materials or bases of the natural mineral paints that 

 occur in New York include iron ores, shale or slate, and ochers. 

 In all the principal coloring agent is an iron compound and usually 

 the ferric oxide, hematite, or the ferric hydrate, limonite. Reds, 

 browns and yellows are the common colors produced. 



Metallic paint may be made from hematite of earthy or massive 

 nature, or from limonite. It is also prepared by calcination of 

 siderite, ferrous carbonate or spathic iron ore, of which the natural 

 gray color changes to red in the operation through the conversion 

 of the carbonate into hematite. The iron sinter from the roasting 

 of pyrite in acid manufacture is also sometimes employed for the 



