PHYSIOGRAPHY. 203 



Feldspar. 



eral species of the Hornblende and Garnet families ; but it may be con- 

 sidered as a rarity in veins, except in those which are composed of the 

 same species of which the rocks consist which they traverse. In these, 

 its varieties are accompanied by Axinite, Quartz, several ores of titani- 

 um, Calcarious Spar and other species ; and have their surface some- 

 times covered with scaly particles of Talc. Sometimes the crystals have 

 their surfaces, particularly the planes M, covered with crystals of Al- 

 bite, disposed in parallel position. 



The finest crystals of Adularia are found in the highest districts of St. 

 Gothard, and the Alps of Savoy ; several varieties occur also in Salzburg, 

 the Tyrol, Bavaria, Dauphiny, the isle of Arran, in Cornwall and Wales. 

 Very large crystals of Feldspar are found in Siberia, which are general- 

 ly penetrated by Quartz, sometimes of considerable transparency. Am- 

 azon stone, a verdigris- green variety, associated with small white crys- 

 tals of Albite, occurs near Fort Troitzk in the Uralian mountains. Com- 

 pact Feldspar, forming the body of clinkstone-porphyry, is found in the 

 Bohemian Mittelgebirge, in the western isles of Scotland, at Sahla in 

 Sweden, in the Hartz, &c. Variolite has been noticed from Piedmont 

 and Corsica. The finest varieties of porcelain earth are those from Chi- 

 na, where it is called Kaolin, from Saxony, from Passau, and from Li- 

 moges in France. 



The United States have thus far afforded few handsomely crystallized 

 specimens of the present species, although they have been quoted from 

 a number of localities. The most interesting of these are Rossie and 

 Governeur in St. Lawrence co. (N.Y.) Greenfield near Saratoga in the 

 same state, and Haddam, (Conn.) At the first mentioned place it is as- 

 sociated with crystallized, white Hornblende and Scapolite in limestone, 

 and at the two last with Chrysoberyl, Garnet and Tourmaline in a gra- 

 nitic vein. A few crystals have been afforded, apparently belonging to 

 this-specics, at Franconia, (N.H.) in a vein made up chiefly of large crys- 

 tals of Epidote and Quartz. Crystallized Feldspar in-small quantity, fre- 

 quently accompanies Beryl in N. England ; and is met with also in loose 

 masses, lining small cavities in a rock made up of Hornblende, Au- 

 gite, and massive Feldspar. The crystals are often deeply imbedded 

 in Calcareous Spar. Under these circumstances, it has been found 

 at Middlefield and Becket, (Mass.) Feldspar exists in very large im- 

 perfect crystals, disseminated through gneissj and imparting to it a por- 

 phyritic appearance, throughout the primitive region of New England. 

 It is found of a verdigris green color, crystallized and massive, at Bever- 

 ly, (Mass.) The flesh-colored varieties appear to abound more in the 



