PHYSIOGRAPHY. CLASS n. 



veins, and is accompanied by various ores of silver and 

 lead, and often intimately mixed with pyramidal Copper- 

 py rites and hexahedral Lead -glance. Also rhombohedral 

 and macrotypous Lime-haloide and pyramidal Euchlore- 

 mica occur along with it. 



3. Its chief localities are Johanngeorgenstadt, Marien- 

 berg, Annaberg and Schneeberg in Saxony, and Joachims- 

 thai and Fribus in Bohemia. In Cornwall it has been 

 found in the tin-mines of Tincroft and Tolcarn near Ited- 

 ruth. 



4. It is used in painting upon porcelain, and yields a 

 fine orange colour in the enamelling fire, and a black one 

 in that in which the pprcelain itself is baked. 



GENUS VIII. CERIUM.ORE. 

 1. UNCLEAVABLE CERIUM-ORE. 



Indivisible Cerium-Ore, or Cerite. JAM. Syst. Vol. III. 

 p. 183. Uncleavable Cerium-Ore. Man. p. 241. Cer- 

 ite. PHILL. p. 263. Cerinstein. WERN. Hoff'm. H. 

 B. IV. 1. S. 286. Cerent. HAUSM. S. 303. Cererit. 

 LEONH. S. 388. Cerium oxyde silicifere. HAUY. 

 Tabl. comp. p. 120. Cerium oxide' siliceux rouge. 

 Traite, 2de Ed. T. IV. p. 393. 



Regular forms and cleavage unknown. 



Lustre adamantine. Colour, intermediate between 



clove-brown and cherry-red, passing into grey. 



Streak white. Translucent on the edges. 

 Brittle. Hardness = 5-5. Sp. Gr. = 4-912. 



Compound Varieties. Massive : composition gra- 

 nular, individuals not distinguishable ; fracture un- 

 even and splintery. 



OBSERVATIONS. 



1. According to HISIKGER, it consists of 



