MINERAL RESOURCES OF THF STATE OF NEW YORK /I 



Manufacturers of enamel ware, glazed brick and terra cotta 

 consume considerable quantities of feldspar. In enamel ware the 

 requirements are perhaps not so strict in regard to iron as in pottery- 

 manufacture, but the spar must be fairly free of quartz as the latter 

 tends to raise the melting point. Among enamel ware and terra 

 cotta manufactures a preference is occasionally shown for albite 

 over potash feldspar owing to its lower fusing point. Little of this 

 variety, however, is found in the New York pegmatites. Feldspar 

 is used in the manufacture of opalescent glass. This requires a 

 material of about the same quality as that for enamel ware, but 

 may contain more quartz. 



A large quantity of feldspar is employed as abrasive, especially 

 in the form of scouring soaps and powders. For that purpose it 

 is ground to an impalpable powder. It also finds use in the manu- 

 facture of abrasive wheels as a binder for the emery or carborundiun 

 with which the spar is mixed. 



Unsorted pegmatite when crushed finds sale among makers of 

 prepared roofing in which it is employed as a surface coating with 

 tar or some bituminous binder. 



The pegmatite is crushed to pea size or a little coarser and the 

 feldspar by reason of its cleavage yields a flat surface that firmly 

 adheres to the paper. Purity of the material is a subordinate factor 

 and no effort is made usually to separate the different ingredients. 

 The fine material resulting from the crushing is sold for use in 

 concrete and grout and a small proportion of the coarser sizes finds 

 a market as poultry grit. Crushed pegmatite has recently come 

 into use in the preparation of artificial stone which is made to 

 imitate granite and is cast in almost any form so as to require little 

 or no tool dressing. 



Production. The production of feldspar in New York State 

 during the past few years has averaged between 10,000 and 15,000 

 short tons, inclusive of crude and ground feldspar and crushed 

 unsorted pegmatite. The following table covers the period 1904-18 

 in which statistics have been collected by this office. The figures 

 as given comprise a few thousand tons each yiear of quartz obtained 

 in connection with the production of feldspar at the Kinkel quarries 

 jn Westchester county. 



