58 Troost on the Pyroxene. 



ble crystals. It offers various forms which are proper to 

 this substance — we have 



Cylindroid P. The crystals of the Sahlite, Diopside, and 

 Mussite, are often marked by longitudinal striae or small 

 channels, which give them a cylindrical appearance. 



Lamellar P. The Sahlite is remarkable by its lamellar 

 structure — It occurs in great or small lamellae. It offers 

 also very small lamellar particles, in which case it belongs 

 to the Grano-lajnellar variety. The Augite P. is also some- 

 times lamellar.- 



Compressed P. The crystals of the Mussite exhibit often 

 this form. 



Granular P. This structure is proper to the variety 

 Coccolite. It occurs also in the green Volcanic Pyroxene, 

 and in the Jiugite. 



Fibro granular P. This is the variety Mussite. 



Fasciculated radiated P. In masses formed by the union 

 of prisms as bundles or rods, fascicular — This occurs in the 

 Island of Elba with the Yenite, and in the Mussite. 



Fibrous P. This variety differs from the former in the 

 prisms being more slender, which make it resemble some 

 varieties of Asbestos. 



Shistose P. Formed by a lamellar accumulation, as in 

 the Mussite, and a variety found at Franklin, called Jeffer- 

 sonite. 



Resinoid P. This variety is black, having the appear- 

 ance of pitch, and is void of all appearance of any crystal- 

 ine structure. It belongs to the Volcanic Pyroxene. 



Having now exhibited the different characters and man- 

 ners in which the Pyroxene offers itself to our observation. 



