REPORT OF THE DIRECTOR I916 257 



these have a rounded, lenticular or irregular shape as seen on the 

 surface, while the concealed portion is likely to be variable as well. 

 Some pegmatites occur in normal granites as local differentiation 

 phases and show gradation by imperceptible stages on the borders, 

 but such rarely exhibit so coarse crystallization as the separate 

 intrusions. The size of the crystal individuals is a factor of prac- 

 tical importance, since it affects more or less the work of sorting 

 and cobbing. In all quarry operations, except those connected with 

 the production of roofing material, there is considerable waste in 

 the preparation of the shipping product, the proportion varying with 

 each separate occurrence. In some the loss may amount to fully 

 one-half of the rock broken down, represented by quartz, lime-soda 

 feldspar, and the less important silicates like mica, hornblende, 

 tourmaline etc., the presence of which is detrimental to the use of 

 the spar for pottery manufactiu*e. 



The other factors that need to be considered are the situation 

 with respect to shipping facilities and the distance to market. The 

 selling prices, which in recent years have ranged between $3 and 

 $5 a long ton for selected crude spar of pottery grade, impose 

 narrow limits upon the costs of haulage and freights. The market 

 centers are Trenton, N. J., and East Liverpool, Ohio, where are 

 situated the largest pottery manufacturers. The local pottery 

 industry, though important, does not afford a sufficient outlet for 

 the quariy product of the State. 



GARNET 



The production of abrasive garnet last year was stimulated by the 

 widespread industrial activity and by the curtailment of supplies 

 of foreign abrasives owing to the high ocean freight rates. The 

 Adirondack mines, which yield the larger part of the domestic 

 supply, reported a gain of about 50 per cent in the year's ship- 

 ments, a very encouraging increase after the general dulness which 

 has obtained in the industry in recent years. The output has 

 averaged around 4000 tons, and only a few times has it exceeded 

 5000 tons. The output for 191 6, however, established a new record. 



The largest operations in the Adirondack region were carried on 

 by the North River Garnet Co., at Thirteenth Lake, near North 

 River, Warren county. This company has a large, open quarry 

 in a great body of garnetiferous gneiss that consists of acid feld- 

 spar and hornblende, with garnet crystals rather plentifully distri- 



