86 NEW YORK STATE MUSEUM 



texture is to be ascribed. Occasionally masses of very large fibers 

 in cJDScly compacted parallel arrangement are met with, very similar 

 in appearance to amphibole asbestos. The usual grade, however, 

 consists of a belted mass of interlacing fibers, seldom more than a 

 fraction of an inch in length, and sometimes so fine as to resemble 

 massive talc. 



On the western end of the talc belt, the mineral is quite often 

 foliated. Certain mines in this section yield the foliated variety 

 in quantity, as intercalated seams in the fibrous talc. The name 

 rensselaerite has commonly been applied to the foliated variety, 

 but such usage is not warranted. The type specimens of rens- 

 selaerite collected and described by Ebenezer Emmons show it to 

 be harder than talc and more nearly allied to serpentine in physical 

 character, while it is an alteration product of pyroxene. The foli- 

 ated talc is white with often a greenish tint and at times yields 

 quite large and transparent leaves, resembling selenite. 



Near the surface the deposits show discoloration from iron and 

 organic matter, but at a little depth they yield material which when 

 ground is a beautiful opaque white, light in texture and very 

 uniform. 



The only defect ■ in the talc from this section is the presence 

 oftentimes of a certain amount of grit which is hard to eliminate 

 from the ground product. It can be traced to fine particles of quartz 

 disseminated through the talc and in the case of the fibrous variety 

 also to the existence of some unaltered tremolite. Samples of the 

 prepared fiber when examined under the polarizing microscope will 

 commonly reveal a little of the original tremplite. The proportion 

 of grit is so small as to have little or no effect upon the uses of 

 the talc for many purposes, yet it limits the market to some extent, 

 and efforts have been made to devise a method for its separation, 

 though up to the present time without much success. 



Mining of talc. The mine openings are situated along the out- 

 crop of the talc beds which have a northeasterly strike in con- 

 formity with that of the inclosing limestones. With the exception 

 of the mines owned by the Union Talc Co. near Silvia lake on the 

 southwestern end of the belt they lie in proximity to the Oswe- 

 gatchie river, which furnishes most of the power used in the talc 

 mills. The American and Arnold mines of the Union Talc Co. are 

 2 or 3 miles south of the river. In the central part of the belt near 

 Fullerville the Ontario Talc Co. owns three mines. The eastern 

 portion of the belt around Talcville includes the mines of the 



