PHYSIOGRAPHY. 175 



Scapolite Scheeletine. 



Numerous localities of Scapolite are found in the United States. Beau- 

 tiful crystals of the form of fig. 388, are found at Governeur, (N. Y) dis- 

 seminated through a coarsely granular Calcareous Spar. Large crys- 

 tals of a white variety rarely terminated with regularity, occur penetra- 

 ting Quartz, which itself forms veins in white limestone at Bolton and 

 Boxborough, (Mass.) Nuttallite is found also at Bolton in implanted 

 crystals, rarely surmounted by four-sided pyramids. A purple variety 

 exists at the same place, forming considerable masses, made up of large 

 columnar individuals. Compact varieties occur at Boxborough and 

 Westfield, (Mass.) A fibrous one is found at Monroe, (Connecticut.) 

 Crystallized specimens are afforded by the white limestone of Amity, 

 (N. Y.) 



SCARBROITE. 



Massive : composition impalpable. Fracture conchoidal. 



Dull. Color white. 



Very fragile. Sp. gr. 1-485. 



1. It absorbs water without becoming more transparent. 



2. Analysis. 



Silica . . 10-50 . . . 7-90 



Alumina . , 42-50 . . . 42-75 



Oxide of iron . . 0-25 . . . 0-80 



Water . . 4675 . . . 48-55 



3. It is found in little veins in greywacke in the great hill of Scar- 

 borough, England. 



4. It is probably a mere mechanical aggregate, similar to clays in 

 general. 



SCHAALSTEIN. (See Tabular Spar.) 

 SCHEELETINE. Tungstic Lead-Baryte. 



Primary form. Octahedron with a square base. P on 

 P over the base =131 29' 33". 



Secondary form, the primary, having the edges of the 

 base and the pyramidal edges truncated, together with the 



