APPENDIX. 327 



ISOPYRE. Isopyric Quartz. HAIDINGER. (See 

 Vol. I, p. 287.) 



It forms compact masses occasionally two inches in diameter in the 

 granite of St. Just near Penzance, where it occurs associated with Tin 

 Ore and Tourmaline. The Tachylite is found in basalt and wacke, at 

 Sasebiihl near Gottingcn. 



KUPAPHRITE. (See Vol. I, p. 295.) 



It is found at the mines of Cohonas do Campo in Brazil, associated 

 with Quartz and Magnetic Iron Pyrites. 



LAUMONITE. 



It is found in considerable quantity at Keweena Point, Lake Superi- 

 or, in amygdaloid. Its color is reddish white, sometimes nearly- brick- 

 red, and its structure coarse granular. It is mingled with Calcareous 

 Spar, and appears to be less prone to decomposition than the white 

 varieties. 



LEADHILLITE. (See Vol. II, p. 6.) 



The primary form of this species according to HAIDINGER and 

 BREWSTER is prismatic, instead of rhombohedral. The left hand e fig. 

 275, inclines to the central e under 120 20', and the central e to that 

 on the right hand under 119 50' ; a on the left hand e =90 29'. 



NATRON.* (See Vol. II, p. 77.) 



It is often observed within the crater of Vesuvius sublimated among 

 the crevices of hot lava. It is common also on the walls of old mines 

 and cellars. The most abundant deposit is the soda-lakes of Egypt ; it 

 likewise occurs in the hot springs of Carlsbad in Bohemia and Kykum in 

 Iceland. 



ONKOSIN. 



Massive : composition impalpable. Fracture splintery to imperfectly 

 conchoidal. Color light apple-green, to greyish and brownish. Lustre 

 vitreous to resinous. Translucent. Hardness between 2-0 and 3-0. Sp. 

 gr. =2-80. 



1. Before the blow-pipe, swells up and easily melts into a white, 

 blebby, vitreous and somewhat translucent glass. With borax, it grad- 

 ually forms a transparent and colorless glass. 



