274 PHYSIOGRAPHY. 



Hypersthene. 



Lustre eminently metallic-pearly, upon the most perfect 

 diagonal cleavage ; in other directions, more or less dis- 

 tinctly vitreous. Color greyish, brownish or greenish- 

 black ; several varieties almost copper-red upon the perfect 

 face of cleavage. Streak greenish-grey. Opake; in some 

 varieties, slightly translucent on the edges* 



Brittle. Hardness =6*0. Sp. gr. =3-389. 



Compound Varieties. Massive : composition granular, 

 individuals sometimes of considerable size; faces of com- 

 position uneven and rough. 



1. If heated alone, it is little altered in appearance, but melts upon 

 charcoal into a greenish-grey, opake globule, easily soluble in borax. 

 2. Analysis. 



By KLAPROTH. 



Silica .... 54-25 



Magnesia .... 14-00 



Alumina .... 2-25 



Lime .... 1-50 



Oxide of iron .... 24-50 

 Water - 1,00 



Manganese . - -. a trace. 



3. Hypersthene occurs engaged in a mixture of Labradorite and Py- 

 roxene. The rock often contains Magnetic Iron-Ore, and seems to be 

 analogous to sienite or greenstone. It exists also in a slaty rock with 

 Garnet, in serpentine along with Saussurite, and in white limestone 

 along with Spinel and Brucite. 



4. It was first brought from the coast of Labrador. It is quoted from 

 Cornwall, England, where it is said to occur in serpentine, and from 

 Greenland, where it exists in primitive slate. The variety, Jiowever, 

 from the last mentioned place, with a blue opalescence parallel to the 

 shorter diagonal of the prism, presents two faces of cleavage inclined at 

 an angle of about 124? 30', and must be referred to the species Horn- 

 blende. 



Hypersthene has within a few years been met with in Orange county, 

 (N.Y.) at Warwick, In the formation of limestone, with which is associ- 

 ated serpentine, and which is so abundant in Spinel and Brucite. It oc- 



