% 



oj Boston and its Vicinity^ 



13P 



tjt Scratch glass^ do not yield to the knife 



SPECIES 



Subspecies 



I. 



I. — Common ^uart%. Sliining and vitreous lustre j crystalliz- 

 ed in hexagonal prisms ; amorphous 5 splintery; con- 

 choidal. 



Var. L Limpid Qiiartz, Colourless; tra:isparent; amorphous. 



J. 



u.'-^Honistone. 



Grey ; dull ; splintery ; t^ugh ; becomes 



white hcfore the hlowpipe. 



Division ii. — Fusible before the blowpipe. 



§ Hardness equal or superior to that of common tvindow glass^ soinetim^'^ 



yields slightly to the Jinife^ 



t Fields a black glass ^ or enameL 



r 



YIJl.— Common Garnet, Red and brownish red ; crystallized 



in double eight-sided pyramids acuminated by four 



planes. 



XIV. 



II. 



V 



Basaltick Hornblende, Black ; shining ; crystal- 

 lized in single hexagonal prisms. 



14. Fields a white glass or enameL 



Y,-^Feldspar. Red, black, and white; amorphous, and 



crystallized in tables and rhombs; lamellar structure. 



XI. 



I. 



Chelmsfordite, Whitish, greenish ; pearly ; crys- 

 tallized in rectangular prisms ; phosphorescent 



by heat. 



J 



§ Field to the knife, sometimes feebly scratch glass* ^ 



t Field a white glass or enameL 



Far. I* Common Tremolite. Whitish, greenish ; pearly i 

 fibrous, passing to imperfectly foliated* 



■j^ 





