ZIRCONIA. 



381 



zoned appearance around tlie terminations. One of tliese being accidentally broken, I found 

 a rounded mass of white carbonate of lime in the centre, occupying nearly the whole interior, 

 while the faces were all perfect, and indeed quite highly finished. Whether this is in all 

 cases the cause of the parti-coloured appearance of these crystals, I am unable to say, but it 

 is more than probable that such is the case. The fact is curious, as showing that the pre- 

 sence of foreign bodies docs not necessarily present any oljslacle to the process of crystal- 

 lization. Similar appearances are presented in the crystals from Johnsburgh. Some of these 

 crystals also have been broken, and the terminations moved from their original situation, as 

 shown in the figures given by Dr. Emmons in his report, and which he has obligingly per- 

 mitted me to introduce. Fig. 431 exhibits the appearance of the broken crystals of zircon; 

 Fig. 432 represents a bent crystal of apatite, associated with the zircon. 



Fig. 431. 



Fi;. 132. 



Fig. 433. 



Fig. 435. 



Warren County. The largest and most interesting crystals of zircon heretofore found in 

 this State occur at Johnsburgh in this county. One of these is a modification of the dioctae- 



dre of Haiiy, Fig. 433 ; and 

 to this may be added the 

 forms given in Figs. 434 

 and 435 ; and those repre- 

 sented in Figs. 415 and 418. 

 The measurements have al- 

 ready been introduced, and 

 need not be repeated. 



All the figures from the 

 preceding locality have been 

 drawn from specimens in 

 the Cabinet of Dr. Emmons. 

 The crystals were from half 

 an inch in length, and from a quarter to half an inch in diameter, 

 with all the planes perfect, and often very highly finished. They arc of a reddish brown 

 colour, with usually a lighter central portion as in the specimens from Hammond in St. Law- 

 rence county, and arc opaque or feebly translucent. 



an inch to three-quarters of i 



