24ri DESCRIPTIONS OF MINERALS. 



Enstatite. 



Trimetric. I A 7=88° 16'. Prismatic cleavage easy. 

 Usually possesses a fibrous appearance on the cleavage sur- 

 face. Also massive and lamellar. 



Color, grayish, yellowish or greenish-white, or brown. 

 Lustre pearly : often metalloidal in the bronzite variety. 

 H. 5-5. G. 3-1-3-3. 



Composition. Mg 3 Si = Silica 60, magnesia 40. B.B. in- 

 fusible, and insoluble. Bronzite has a portion of the mag- 

 nesium replaced by iron. 



Diff. Resembles amphibole and pyroxene, but is infusi- 

 ble, and trimetric in crystallization. 



Obs. Occurs in the Vosges : Moravia ; Bavaria ; Baste, 

 in the Hartz; Leiperville and Texas, Pa.: Brewster's, X. Y. 



Hypersthene is very near bronzite in crystalline form and in com- 

 position. It contains a larger percentage of iron, and on being heated 

 B.B. on charcoal it becomes magnetic. Occurs at St. Paul's Island, in 

 Labrador ; Isle of Skye ; in Greenland ; Norway, etc. 



Wollastonite. — Tabular Spar. 



Monoelinic. Rarely in oblique flattened prisms. Usually 

 massive, cleaving easily in one direction, and showing a 

 lined or indistinctly columnar surface, with a vitreous lustre 

 inclining to pearly. 



Usually white, but sometimes tinged with yellow, red or 

 brown. Translucent, or rarely subtransparent. Brittle. 

 H. = 4-5-5. GL =2-75-2-9. 



Composition. Ca 3 Si = Silica 52, lime 48 = 100. B.B. 

 fuses with difficulty to a subtransparent, colorless glass; in 

 powder decomposed by hydrochloric acid, and the solution 

 gelatinizes on evaporation: often effervesces when treated 

 with acid on account of the presence of calcite. 



Diff. Differs from asbestus and tremolite in its more viter- 

 ous appearance and fracture, and by its gelatinizing in acid; 

 from the zeolites by the absence of water, which all zeolites 

 give in a closed tube : from feldspar in the fibrous appear- 

 ance of a cleavage surface and the action of acids. 



Obs. Usually found in granite or granular limestone ; 

 occasionally in' basalt or lava. Occurs in Ireland at Dun- 

 more Head ; at Vesuvius and Capo di Bove : in the Hartz ; 

 Hungary ; Sweden ; Finland ; Norway. 



At TVillsboro', Lewis, Diana, and Roger's Rock, K Y., 



