m 



;4) £121' 



MENAOANE, AND ITS OHES. 



or seated in, the scarcely perceptible clefts of one of those 

 nameless chloritic rocks, which abound so much throughout 

 the Alps in general. That from Aschaffenberg is said to 

 occur in granite; that from Saltzburg is found imbedded in 

 massive common trcmolite. The rutile from Spain and Si- 

 beria is embedded in rock crystal. It would therefore ap- 

 pear that this fossil lays claim to great antiquity, the time of 

 its production falling within the period of the earlier primi- 

 tive rocks, and that the metal it contains probably surpasses, 

 in that respect^ tin, molybdjena, .and tungsten, rieing even 

 with iron and manganese *. 



The above description has been chiefly taken from an 

 attentive examination of the specimens of rutile existing in 

 the best collections of Vienna and Saxony. 



Species It 

 Rutilite. 



iisds. I 



SECOND SPECIES. 

 RUTILITE. 



Calcareo -siliceous titan ore of Kirwan. 

 Titanit of Klaproth. 



External cha- 

 racters. 



EXTERNAL CHARACTERS. 



The colour varies from brownish red to dark reddish 

 brown. Has been hitherto found only crystallized in very 

 rhomboidal four-sided prisms, acutely bevelled at the extre- 

 mities, the bevelling planes set on the obtuse lateral edges. 

 The crystals are small, and very small, seldom middle sized. 

 Exteriorly, they are shining. Interiorly, glistening, with a 

 resinous lustre. The fracture is imperfect and minute con- 



* Von Buch has discovered rutile In layers of quartz, in clay slate 

 (Thonschiefer), near Nuhlbach, in Saltzburg, in the vicinity of metal- 

 lic layers, consisting of copper glance, copper pyrites, iron pyrites, 

 nickel, and rarely native copper: also on the mo.mtain Brennkogl, in 

 the valley of Fusch; where it occurs in mica slate, cither reticularly 

 aggregated in rifts, or in acicular crystals, accompanied by tliose singu- 

 lar cylindrically aggregated crystals of foliated chlorite, in venules of 

 almost coeval formation with the rock itself. — Buch's Geognostiche 

 Beobachtungens — R. J. 



Rutile has also been discovered by Von Humboldt, on the summit of 

 a mountain near Caraccia, in New Granada, at the height of 1316 

 tolses.— R. J. 



choidal. 



