OEDEE VII. TETRAHED11AL BOKACITE. 347 



2. According to KLAPROTH, the present species con. 

 sists of 



Chrysolite. Chrysolite Olivine. 



From the meteoric Iron. 



Silica 3900 4 1-00 50-00. 



Magnesia 43-50 38-50 38-50. 



Oxide of Iron 19-00 18-50 12-00. 



Lime 0-00 9-00 0-25. 



According to some recent researches of Professor STRO- 

 MEYER, the Chrysolite from the meteoric Iron from Siberia, 

 and Olivine also, contain some oxide of nickel. ; Before the 

 blowpipe, prismatic Chrysolite assumes a darker colour, but 

 does not melt, nor lose its transparency. Olivine loses its co- 

 lour in heated nitric acid. Varieties of the present species may 

 be artificially produced by mixing the constituent parts in 

 the required proportions, and exposing them to a high tern- 

 perature. The silicate of the protoxide of iron which pos- 

 sesses the same form of the prismatic Chrysolite, is an im- 

 portant agent in the process of melting copper ores and 

 refining pig-iron. 



3. The original repository of the implanted crystals of 

 Chrysolite is not known : they are said to come from Upper 

 Egypt, and are frequently brought to Europe by way of 

 Constantinople. Less distinct crystals and imbedded grains 

 are found in lava, in various kinds of basalt, &c. ; so in the 

 neighbourhood of Vesuvius, in Saxony, Bohemia, Silesia, 

 Hungary, &c. It occurs in large spheroidal masses, which 

 are not pebbles, mixed with paratomous Augite-spar, in ,the 

 rock called Traptuff, as at Kapfenstein in Lower Stiria, 

 and at the Habichtswald in Hessia." 



4. It is used as a gem of inferior value. 



GENUS. IX. BORACITE. 



1. TETRAHEDRAL BORACITE. 



Hexahedral Boracite. JAM. Syst. Vol. I. p. 335. Oc- 

 tahedral Boracite. Man. p. 220. Boracite. Borate 



VOL. II. 



