Mineralogical Notices. ff 



GLAUKODOTE. BY MM. BREITHAUPT AND PLATTNER. 



[PoggendorfF's Annalen, vol. Ixxvii. p. 127.] 

 Under this name Breithaiipt describes a mineral from the 

 district of Huasco, near Valparaiso in Chili, which furnishes 

 a blue pigment. It has a metallic lustre, and is of a dark tin- 

 white colour. Streak black ; hardness 7 ; brittle; spec. grav. 

 5*975, 5"978, 6*003. Glaukodote occurs in seams in chloritic 

 slate, accompanied by heavy Glanzcobalt (Cobaltine, Cobalt- 

 glanz), and other minerals. According to Plattner, this mineral 

 gives exactly the same reactions before the blowpipe as Co- 

 baltine, and an analysis made by that chemist shows that 

 Glaukodote contains the same per-centage of sulphur as the 

 Cobaltine from Skutterrud, according to Stromeyer; the sum 

 of the quantities of cobalt and iron in the two minerals like- 

 wise agree, but the atoms Fe, Co, S, As are in Glaukodote as 

 2:4:6:6, leading to the formula 2(CoS2+ CoAs^) +(FeS2 

 + FeAs^), which denotes a compound of f Cobaltine and ^ 

 arsenical pyrites. The quantities found, compared with those 

 calculated according to this formula, are — 



Sulphur . . . 20*210 6 = 1200*0 19*40 



Arsenic . . . 43*200 6 2812*5 45*46 



Cobalt . . . 24-774 4 1474*4 23*83 



Iron .... 11-900 2 700-0 11-31 



EMBOLITE. BY MM. BREITHAUPT AND PLATTNER, 



[PoggendorfF's Annnlen, vol. Ixxvii. p. 134.] 



Is the name assigned by Breithaupt to a bromide of silver 

 from the Colorada mine near Copiapo in Chili. It occurs in 

 cubic crystals upon a very ferruginous limestone, is exter- 

 nally of an olive and asparagus green, but in the interior of a 

 sulphur-yellow to finch-green colour. When recently ex- 

 tracted by smelting, it is likewise of a sulphur-colour. It has 

 diamond lustre, hardness nearly 2, perfectly malleable, spec, 

 grav. 5*806. Plattner found 5*789 for a yellow sample ex- 

 tracted by smelting, and 5*790 for a sample of green colour, 

 and in another specimen even above 5*8. 

 Plattner's analysis gave — 



leading to the formula 2AgBr + 3AgCl. 



