PHYSIOGRAPHY. 



Scheeletine Schiller-Spar. 



replacement of the angles at the summit, by four planes, 

 resting on the primary planes. 



Cleavage, parallel with the primary faces, indistinct. 



Lustre resinous. Color green, grey, brown and red. 

 Streak white. 



Hardness =2-75 . . . 3-0. Sp. gr. = 7-904 . . . 8-088. 



1. It is fusible before the blow-pipe, yielding oxide of lead upon the 

 charcoal. With soda, it affords globules of metallic lead. 



2. Jlnalysis. 

 Tungstic acid . . . . . . . 52-00 



Oxide of lead ..... . . 48-00 



3. It is a very rare substance ; and is found in minute crystals, in the 

 tin mines of Zinwald, Bohemia. 



SCHEEVERITE. 



In crystalline grains. 



Lustre pearly, and feebly shining. Color whitish. 



Friable. Rather heavier than water. 



1. By heating, it emits a feeble aromatic empyreurna. It melts, very 

 readily, into a colorless liquid. The melted mineral, on cooling, crys- 

 tallizes into four-sided, acicular crystals. It burns with flame, attended 

 with feeble odor, and without leaving behind any residue. 



2. Jlnalysis. 

 Carbon . . . . . . . 73-00 



Hydrogen ....... 24-00 



3. It is found in loosely aggregated grains, forming nests in a bed of 

 brown coal, at St. Galen in Switzerland. 



SCHILLER-SPAR. Diatomous Schiller-Spar. 

 MOHS. 



Primary form. Doubly oblique prism ? 



Cleavage in two directions, one of them being highly 

 perfect and easily obtained, while the other appears only in 

 slight traces. Inclination between 135 and 145. Frac- 

 ture uneven, splintery. 



