226 PHYSIOGRAPHY. 



Talc. 



4. Common Talc, indurated Talc, Potstone and slaty Chlorite, consti- 

 tute beds in primitive mountains. The latter frequently contains imbed- 

 ded crystals of Magnetic Iron ; some of the former contain Apatite and 

 Rhomb Spar. Common Chlorite in particular, is found in beds in primitive 

 rocks, consisting chiefly of limestone, Hornblende and Magnetic Iron. 

 Soapstone is found in veins in serpentine, and Steatite, in beds in chlo- 

 rite slate and in serpentine. The latter often contains the variety of 

 Dolomite called Bitter Spar. Other varieties, and among them the small 

 scaly crystals of foliated Chlorite, occur in veins of various descriptions, 

 and in the crystal caves of the Alps. Green-Earth, and sometimes also 

 foliated Chlorite, occur in arnygdaloidal rocks, where they are found ei- 

 ther lining the vesicular cavities, or as imbedded nodules in the body of 

 the rock itself. Earthy Talc, or Nacrite, has been found in lead veins. 



5. Those varieties which by themselves form mountain masses, are 

 met with in the primitive districts of the Tyrol, Salzburg, Switzerland, 

 Sweden, Norway, Corsica, &c. ; in the Grampians in Scotland ; in Unst, 

 one of the Shetland isles. Upon beds and veins with metallic ores, &c., 

 they occur in considerable quantity in Cornwall ; also in Saxony, Salz- 

 burg, and Sweden, &c. The crystallized varieties occur in veins, fre- 

 quently in Mount St. Gothard, Salzburg and other countries. The chief 

 localities of the green- earth are the Monte Baldo near Verona, Iceland, 

 the Faroe Islands, Tyrol, Hungary and Transylvania. 



The United States abound in the present species. Soapstone and 

 Steatite form powerful beds and veins in the western parts of Massachu- 

 setts, in New Hampshire, Vermont, and in Rhode Island. At Marlbor- 

 ough, (Vt.) it embraces very perfect crystals of the Rhomb Spar. The 

 same mineral is found in the Steatite of North Providence, (R. I.), but 

 not in distinct crystals. Crystallized varieties are of rare occurrence, ex- 

 cept in globular forms, and then in small quantities. Beautiful colum- 

 nar specimens, of a delicate green color, occur at Smithfield, (R. I.) in 

 Steatite ; and white granular varieties at SmithfieM, in limestone, in the 

 same vicinity. A handsome green Talc is found at Bridgewater in the 

 talcose slate region, with which is intermingled a transparent massive 

 Dolomite. Chlorite abounds throughout New England, and the chlo- 

 rite slate formation is traceable from Vermont to Georgia. 



6. Some of the varieties of Talc, as Soapstone and Steatite, are used as 

 fire stones in iron- furnaces, in stoves for heating houses, and in cu- 

 linary vessels. Green earth is used, both raw as a green color, and burnt 

 as a reddish-brown color, for painting houses, &c. The Venetian Talc 



