334 ROCKS. 



TALCOSE SLATE. TALCOSE ROCK. 



Talcose slate resembles mica slate, but has a more greasy 

 feel, owing to its containing talc instead of mica. It is usu- 

 ally light gray or dark grayish-brown. It breaks into thin 

 slabs, but is generally rather brittle, yet it often makes good 

 fire-stones. 



A talcose slate in Stockbridge, Vt., is worked for scythe 

 stones and hones, and is of excellent quality for this purpose 



Talcose rock is a hard and tough compact rock, containing 

 more or less talc, and often quite compact. It is usually 

 very much intersected by veins of white quartz. Much of 

 it contains chlorite (an olive-green mineral) in place of talc, 

 here and there disseminated. 



Chlorite slate has a dark green color, and is similar in 

 general characters to talcose slate. These slaty rocks are 

 to a great extent the gold rocks of the world, especially the 

 quartzose veins, as mentioned under Gold. Platinum, iri- 

 dosmine, pyrites and many other minerals, occur in them, or 

 in associated beds. 



STEATITE, OR SOAPSTONE. 



Steatite is a soft stone, easily cut by the knife and greasy 

 in its feel. Its color is usually grayish-green ; but when 

 smoothed and varnished it becomes dark olive-green. It 

 occurs in beds, associated generally with talcose slate. 



Owing to the facility with which soapstone is worked, and 

 its refractory nature, it is cut into slabs for fire stones and other 

 purposes, as stated on page 144. The powder is employed 

 for diminishing friction, and for mixing with blacklead in the 

 manufacture of crucibles. It is also used, as observed by 

 Dr. C. T. Jackson, for the sizing rollers in cotton factories, 

 one of which is 4£ feet long and 5 to 6 inches in diameter. 

 The most valuable quarries in Massachusetts are at Middle, 

 field, Windsor, Blanford, Andover, and Chester ; in Vermont, 

 at Windham and Grafton ; in New Hampshire, at Frances- 

 town and Oxford ; in Orange county, North Carolina. The 

 Francestown soapstone sells at Boston at from 36 to 42 dol- 

 lars the ton, or from 3 to 3£ dollars the cubic foot.* 



Steatite often contains disseminated crystals of magnesian 

 carbonate of lime, (dolomite,) and brown spar ; also crys* 

 tals of pyrites and actinolite. 



* Geol. N. H., by C. T. Jackson, 1844 ; p. 168. 



