56 ECONOMICAL MINERALOGY. 



silica in many of its characters ; and when in considerable proportion, it is supposed to have 

 an injurious effect upon the quality of the ore with which it is associated. In its pure or near- 

 ly pure form, it is used for the purpose of giving a yellowish tint to artificial teeth ; and in 

 consequence of its comparative scarcity, and the difficulty of its separation from other sub- 

 stances, is sold at a high price. 



Of the titaniate of iron in the crystalline form, and now known by the name of crichtonite, 

 we have an interesting locality in Warwick in Orange county, where it is imbedded in a dark 

 coloured serpentine ; and variable proportions of titanic acid are also contained in several of 

 the iron ores of St. Lawrrence, Jefferson and Orange counties. 



ORES OF ARSENIC. 



Arsenical pyrites, from which the compounds of arsenic used in the arts are obtained, has 

 been found in this State, in the counties of Essex, Orange and Putnam. 



Essex County. Small veins of this mineral occur in the town of Lewis ; but the quantity 

 which exists there, I have reason to believe, is quite inconsiderable. 



Orange County. There is a locality of arsenical minerals on the lands of Mr. B. Hop- 

 kins, near the village of Edenville, which is particularly deserving of notice. Arsenical py- 

 rites, composed of arsenic, sulphur and iron, occurs here in a vein in the white limestone. 

 Associated with this is the arseniate of iron, or cube ore, as it is called from the primary form 

 of its crystal, which here forms a coating to the preceding, and possesses a beautiful green 

 colour and an adamantine lustre. Every where investing these two minerals is a powder of 

 a lemon-yellow colour, which is ascertained to be the sulphuret of arsenic or native orpiment. 

 In another part of the same vein is found a considerable quantity of the red oxide of iron, 

 which, together with the sulphuret of arsenic, has undoubtedly been produced by the decom- 

 position of the arsenical pyrites. And in addition to these metallic minerals, we have also 

 arragonite in delicately radiated fibres, and of a snow-white colour, and occasionally thin la- 

 minae of transparent sulphate of lime or selenite. On the whole, this is one of our most in- 

 teresting localities, not only on account of the minerals which it affords, but of the apt illustra- 

 tion which it presents of the changes produced in the mineral kingdom through the influence 

 of chemical agencies. 



Putnam County. Near Browm's quarry are two localities of arsenical pjrrites, one of 

 which has, at some former period, been extensively worked. The ore, which might be used 

 for the extraction of arsenic, seems to be abundant ; but the present condition of the mine 

 renders it difficult to arrive at a certain conclusion on this subject. Its reported mixture with 

 silver, is probably one of those stories circulated for selfish purposes ; and the only ground for 

 it in the present instance, is the fact that in other countries the arsenical ores are often asso- 

 ciated with those of a more valuable metal. 



