GENERAL DESCRIPTIONS 



SPECIES. 



LAUMONITE. Diatomous Kouphone-Spar. 

 MOHS. 



Primary form. Oblique rhombic prism : (oblique from 

 an acute edge.) Mon M'=86 15'. M on P=113 30'. 

 Iceland. Nova-Scotia. 



Secondary forms. 



1. Fig. 272. 



M 



M on c 



104 20'. PHILLIPS. 



2. Primitive form, with the lateral edges truncated. 

 Schemnitz, Hungary. 



3. The same, with the addition of plane c, and the trun- 

 cation of the obtuse lateral edges. Huelgoet, Brittany. 



Cleavage, parallel with the shorter diagonal, distinct ; 

 traces of, parallel with the longer. Fracture uneven, 

 scarcely observable. Surface P either smooth or uneven. 



