172 PHYSIOGRAPHY. 



Kather brittle. Soft, BREITHAUPT. Sp. Gr. = 

 10-678, MULLE& VON REICHENSTEIN. 



Before the blowpipe it melts into a metallic globule, and 

 emits a pungent odour. It is soluble in nitric acid, and 

 consists, according to KLAPROTH, of 



Tellurium 44-75. 



Gold 2675. 



Lead 19-50. 



Silver 8-50. 



Sulphur 0-50. 



As yet it is only known from Nagyag in Transylvania, 

 where it occurs with prismatic Tellurium-glance, hexahedral 

 Glance-blende, macrotypous Parachrose-baryte, &c. in veins 

 traversing porphyry. 



YTTRO-CERITE. 



Yttro-cerite. JAM. Syst. Vol. III. p. 566. Man. p. 334. 

 Yttrocerite. PHILL. p. 265. 



Massive. Composition granular, strongly coherent, 



impalpable. Fracture uneven. 

 Colour violet-blue, inclining to grey and white ; 



sometimes white on the surface. Opake. 

 Scratches octahedral Fluor-haloide, and is scratched 



by rhombohedral Quartz, BERZELIUS. Sp. Gr. = 



3-447, BERZELIUS. 



Before the blowpipe it loses its colour, and becomes 

 white before it glows, but is infusible by itself. With sul- 

 phate of lime it melts into a globule, which becomes white 

 on cooling. According to BERZELIUS, it consists of 



Lime 47-63 50-00. 



Fluoric Acid 25-05 25-45. 



Yttria 9-11 8-10. 



Oxide of Cerium 18-22 1 6-45. 



