342 



DESCRIPTIVE MINERALOGY. 



ALBITE. 



[From the Latin albus, white; because the specimens found were of a white colour.] 



Albite. Phillips, TTwmson and Bmdant. — Tetarto-Prismatic FelJspir, or Albite. Jameson. — TetartopTismatiBcber 

 Feld-Spath. Mohs. — Variety of Feldspar. Cleaveland. — Cleavelandite. Brooke and Levy. 



^'S- 325. Description. Colour usually white ; sometimes grey, green or 



brown. Streak white. It occurs regularly crystallized, frequently in 

 twins ; also massive and disseminated. Primary form a doubly ob- 

 lique prism. Fig. 325. M on P 93° ZfT ; M on T 117° 53' ; P on 

 T 115° 5'. Cleavage perfect parallel to M and P, less so to T. 

 Fracture imperfectly conchoidal. Lustre pearly upon cleavage plane, 

 vitreous in other directions. Transparent to translucent on the edges. 

 Hardness 6.0. Specific gravity 2.60 to 2.68. Its behaviour before 

 the blowpipe is similar to that of feldspar. 



Composition. Specimen from Chesterfield, Mass. — Silica 70.68, alumina 19.80, soda 

 9,06, lime 0.23, oxide of iron and manganese 0.11 {Stromeyer). 



Geological Situation. Albite often forms a constituent of greenstone and granite, and is 

 sometimes associated with common feldspar. 



localities. 



According to Dr. Emmons, much of the granite at Gouverneur, in St. Lawrence county, 

 contains albite.* Beautiful white and transparent crystals, often twins, have been found in 

 Granville, Washington county. The specimens, for which I am indebted to Dr. Emmons, 

 exactly resemble those obtained in the vicinity of Castleton, Vermont. 



In Massachusetts, albite is found in crystals, at Williamstown, Chesterfield and Goshen. 

 The crystals are often of considerable size, and twins are not uncommon. 



STELLITE. 



[From the Greek stsXXo, a star ; on account of the star-like arrangement of its crystals,] 

 Stellitc. TTuimson, Dana and Moks (App). 



Description. Colour snow-white. It consists of a congeries of small crystals issuing 

 like rays from several centres. The primary form seems to be an oblique four-sided prism, 

 but the angles cannot be measured. It is tough, and has some resemblance to asbestus and 

 the nemalite of Mr. Nuttall, Lustre silky, shining. Translucent. Hardness 3 , 25. Specific 



* New-York Geological ReporU, 1838. 



