280 PHYSIOGRAPHY. 



lolite. 



IOLITE. Prismatic Quartz. MOHS. 

 Primary form. Regular hexagonal prism. 

 Secondary forms. 



1. Primary, having the terminal edges truncated. 



2. The same, having all its edges, both lateral and ter- 

 minal, truncated ; rarely, also, its angles. 



Cleavage, parallel with M, but very indistinct. Fracture 

 conchoidal. Surface of some crystals rough and dull. 



Lustre vitreous. Color various shades of blue, generally 

 inclining to black. Streak white. Transparent . . . trans- 

 lucent ; blue if viewed in the direction of the axis, yellow- 

 ish-grey if perpendicular to it. 



Hardness =7-0 . . . 7-5. Sp. gr. =2-583 . . . 2-718. 



Compound Varieties. Massive; composition granu- 

 lar, strongly connected, and recognized with difficulty. 



1. Before the blow-pipe, it melts in a good heat, but with difficulty* 

 and only on its edges, into a glass not inferior to the mineral, either in 

 color or transparency. 



2. Analysis. 



By GMELIN. By STROMEYER. By Dr. BRANDES. By BONSDORFF. 



var.Steinheilite,. 



3. lolite occurs in aggregated crystals with Garnet, Quartz, &c. at 

 Cabo de Gata in Spain, in the bay of San Pedro; and this variety has 

 been called lolite. Peliom is found at Bodenmais in Bavaria, sometimes 

 in very distinct crystals, but generally massive, with Magnetic Iron- 

 Pyrites. It occurs with Feldspar and Garnet, in fine crystals, at Ujord- 

 iersoak in Greenland^ at Arendal in Norway, and at Orijerfvi in Finlapd : 



