ON THE DIOPSIDE. \() 



rectangle, the other in its bases, which are rhombs inclined 

 to the sides of the prism. From this circumstance Mr. Haii^ 

 lias suggested the name of diopside (double face.) 



II. Indeterminate varieties of form. Indeterminate 



varieties. 



S. Compressed and laminiform diopside*. While Mr. Compressed Sc 

 Haiiy was examining the crystalline forms of the new spe- lammiform • 

 c^ies, Mr. Tondi, a mineralogist of distinguished merit be- 

 longing to the Museum of Natural History, looking over 

 the collection Mr. Bonvoisin had sent, which was accompa- 

 nied by a systematic catalogue, observed the flattened va- 

 riety among some specimens of a different species. This 

 variety, which belongs to the mussite, afforded Mr. Haiiy 

 the mechanical division, by which the species is character- 

 ized. 



4. Cylindroid diopside: in prisms full of grooves or striae. Cylindroid. 



5. Compact diopside. If we examine attentively the c ompact . 

 crystals of mussite, we see them prolonged in an uninter- 

 rupted series into a compact mass, which serves as their 

 gangue, is of the same colour, though often not so dark, 



and cannot fail to be perceived to be the same substance, 

 though in a less perfect state of crystallization, as Mr. Bon- 

 voisiii conjectured. 



The colours of the diopside are green, greenish gray, Colours. 

 greenish white, and yellowish white. It is sometimes trans- 

 lucid, sometimes opake. 



The crystals of mussite are small, elongated, and com- Cta j s 

 monly opake. Several are twisted, and exhibit the primitive 

 form very undecidedly. The crystals of alalite are in gene- 

 ral larger, translucid, and of a greenish white. 



The mussite has been found in the commune of la Balme- \f u <; S ;t e w her« 

 de-Mussa, in the department of the Po, toward the north of found. 

 the valley of Lans, in the interstices of a vein one or two 

 yards thick, that traverses, at the height of four or five yards, 

 a rock called the Black Rock, which is twelve or fifteen 

 yards high. The crystals have sometimes a translucid gra- 

 nular carbonate of lime for their gangue. 



* This variety of form answers to what Werner calls strahliger, radi- 

 ated. 



C 2 The 



