SILICA. 



261 



Also the forms represented in Figures 134, 135, 13G, 137, 138, and tlic twins 139 and 140. 

 These crystals are usually small. 



Fig. 134. 



Fig. 135 



Fig. 13C. 



Fig. 137. 



Fig. 138. 



Fig. 130. 



Fig. HO. 



Similar crystals are obtained in the slate near the paper mill, two miles west of Catskill ; 

 and during tiic process of excavations that were made for the railroad, large and beautiful 

 crystals were sometimes thrown out. 



Herkimer County. Uncommonly beautiful specimens of rock crystal, perfectly transpa- 

 rent, have been found in various parts of this county, especially at Middlcville, Fairfield, 

 Little-Falls, Salisbury and Newport. They are found sometimes in cavities in the calciferous 

 sandstone; and at others, they lie loosely in the sand, jirobably produced by tiio disintegration 

 of the rock. Mr. Vanu.xem has remarked, tiiat there is probably no locality in the world 

 which produces more perfect or more beautiful (|uartz crystals than Middlcville ; and with an 

 equal refractive power, they would rival llie diamond. They are found of various sizes, and 

 variously grouped. Perfect crystals have seldom been found here of more liian two or three 

 inches in length, while those of from lluvc quarters of an ineii to an inch are very abundant. 



