90 PHYSIOGRAPHY. 



Opal Orpiment. 



varieties are met with in metalliferous veins, along with Galena and 

 Blende. It also occurs in petrifactions in sandstone. 



5. Opal is found more plentifully in Hungary than in any other Euro- 

 pean country. The only deposit of Precious Opal in that country, is at 

 Czerwenitzanear Caschau, along with common and semi-opal, in a kind 

 of porphyry. Traces of it have been met with at Hubertsburg. Fine 

 varieties have lately been discovered in the Faroe islands; and most 

 beautiful ones, sometimes quite transparent, near Gracias a Dios in the 

 province of Honduras, America. Common Opal occurs in great quanti- 

 ties, at Telkobanya near Eperies, and in other parts of Hungary ; in the 

 Faroe islands, in Saxony, &c. An apple green variety is found at Ko- 

 senititz in Silesia, with Chrysoprase ; and the red and yellow, bright 

 colored varieties of Fire Opal, near Zimapan in Mexico. Semi-Opal 

 occurs in several of the countries mentioned above ; also near Frankfort, 

 on the Maine, in Austria, Moravia, Poland, Siberia, &c. In Saxony, 

 Bohemia and Cornwall, it is met with in metalliferous veins. Hyalite is 

 found in amygdaloidal rocks, near Frankfort, in irregular veins ; near 

 Schemnitz in Hungary, in porphyry ; also in Bohemia and various other 

 countries. Meniiite occurs at Menil Montant near Paris. Opal-Jasper 

 is formed, wherever Opal happens to be mixed with oxide of iron, as at 

 Telkobanya in Hungary, near Almas, and Tokorci in Transylvania. 

 Wood-Opal is frequently found at Kremnitz and Telkobanya in Hungary, 

 and in many districts of Transylvania, sometimes in very large trees. 

 The only variety hitherto found in the United States, is the Hyalite, 

 which occurs in Burke and Scriven cos., (Georgia,) lining cavities in a 

 siliceous-shell rock. The siliceous-sinter variety occurs in small quan- 

 tity at the Suanna spring in Florida. 



6. Precious Opal, when possessing vivid colors, is highly prized as a 

 gem ; and is generally cut with a convex surface, 



ORPIMENT. Yellow Melacone Blende. 

 MOHS. 



Primary form. Right rhombic prism. M on M = 

 100. 



