BORON GROUP. 97 



slightly inclined to green. Thin laminae very flexible ; not 

 elastic ; leaves a trace on paper, like graphite, but its color 

 is slightly different, being bluish-gray. 



Composition. Mo S 2 = Sulphur 41*0, molybdenum 59-0= 

 100. B.B. infusible, but when heated on charcoal, sulphur 

 fumes are given off, which are deposited on the coal. Dis- 

 solves in nitric acid, excepting a gray residue. 



Diff. Resembles graphite, but differs in its paler color 

 and streak, and also in giving fumes of sulphur when heated, 

 as well as by its solubility in nitric acid. 



Obs. Occurs in granite, gneiss, mica schist, and allied 

 rocks ; also in granular limestone. It is found in Sweden, 

 at Arendal in Norway, in Saxony, Bohemia, at Caldbeck 

 Fell in Cumberland, and in the Cornish mines. 



In the United States it occurs in Maine at Blue Hill Bay, 

 Camdage Farm, Brunswick, and Bowdoinham ; in New 

 Hampshire at Westmoreland, Landaff, and Franconia ; in 

 Massachusetts at Shutesbury and Brimfleld ; in Connecticut 

 at Haddam and Saybrook ; in New York near Warwick ; in 

 New Jersey near the Franklin Furnace. 



Molybdenum does not occur native. An oxide is occa- 

 sionally found in yellow incrustations on molybdenite, as a 

 result of its alteration. It occurs, combined with lead, as a 

 molybdate (page 151), and this is the only native salt con- 

 taining it. The name molybdenum is from the Greek mo- 

 lubdaina, meaning mass of lead, and alludes to the resem- 

 blance of molybdenite to graphite. 



Ttjngstite, or Tungstic ochre. A yellow powder or incrustation oc- 

 curring with, wolfram, and a result of its decomposition. Occasionally 

 observed at Lane's Mine, Monroe, Conn. 



Besides this oxide there are the native compounds, iron tungstate 

 or wolfram (p. 183), lead tungstate (p. 151), and calcium tungstate. 

 Tungsten also occurs sparingly in some ores of columbium, as in cer- 

 tain varieties of the minerals pyrochlore, columbite, and yttro-colum- 

 bite. 



II. BORON GROUP. 



In Boron, as in the Sulphur group, the most prominent 

 oxide is a teroxide. 



Sassolite. — Boracic Acid. Sassolin. 



Occurs in small scales, white or yellowish. Feel smooth and 

 unctuous. Taste acidulous and a little saline and bitter. 



