290 PHYSIOGRAPHY. CLASS II. 



white. The compact varieties melt more easily and with 

 a slight effervescence. It is dissolved with considerable 

 effervescence by borax, and forms with it a clear globule. 

 If previously burnt and reduced to powder, it loses its co- 

 lour and forms a jelly with acids. 



3. Nothing is known with certainty in regard to the 

 geological rektions of the present species. From its mix- 

 ture with limestone, it seems to be found originally in 

 beds. But it is also said to have been found in veins travers- 

 ing primitive rocks. It is generally associated with hexa- 

 hedral Iron-pyrites. 



4. Dodecahedral Azure-spar has been long ago brought 

 from Lesser Bucharia, Thibet, and China. It has been 

 lately found at Lake Baikal in Siberia, as it is said, in veins 

 with hexahedral Iron-pyrites, prismatic Feld-spar, and do- 

 decahedral Garnet. 



5. Ultramarine is obtained from it. It is also cut into 

 various ornamental articles, as ringstones, snuff-boxes, &c. 



2. PRISMATIC AZURE-SPAR. 



Prismatic Azure-spar, first subsp. JAM. Syst. Vol. I. p. 

 392. Prismatic Azure-spar. Man. p. 180. Lazulite. 

 Azurite. PHILL. p. 94. Lazulit. WERN. Hoffm. H. B. 

 II. 1. S. 285. Korniger Lazulith. HAUSM. II. S. 372. 

 Lazulith (in part). LEONH. S. 415. Lasulit de Werner. 

 HAUY. Tabl. comp. p. 62. Lazulite. Traite', 2de Ed. 

 T. III. p. 54. 



Fundamental form. Scalene four-sided pyramid. 

 Vol. I. Fig. 9. 



Simple forms. |P 2 ? ; f P 2 ? ; P ; 

 P +jx = 91 30' ; Pr = 5830'; Pr = 5920'. 



Char, of Comb. Prismatic. The crystals of this mi- 

 neral possess in general a great deal of resem- 

 blance with those of prismatic Sulphur. As in 



