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DESCRIPTIONS OF MINERALS. 



Titanite. — Spliene. 



Monoclinic. In verv oblique rhombic prisms ; the lateral 

 faces making angles often of 76° 7', 113° 31' (I A I), 136° 12' 



(2A2), or 133° 



The crystals are usually thin with 



sharp edges. Cleavage in one direction sometimes perfect. 

 Occasionally massive. 



Color grayish-brown, ash-gray, brown to black; some- 

 times pale yellow to green ; streak uncolored. Lustre 

 adamantine to resinous. Transparent to opaque. H. = 5- 

 5-5. G. =3 -3-3*6. 



Composition. CaTi0 5 Si = Silica 30*6, titanium dioxide 

 40*82, lime 28*57 = 100 ; in dark brown and black crystals, 

 some iron replaces part of the calcium. B.B. fuses with 

 intumescence. Imperfectly decomposed by hydrochloric 

 acid. 



The dark varieties of this species were formerly called 

 titanite, and the lighter spliene. The name spliene alludes 

 to the wedge-shaped crystals, and is from the Greek spheti, 

 wedge. Greenovite is a variety colored rose-red by manga- 

 nese. 



Biff. The thin wedge-like form of the crystals, in general, 

 readily distinguish this species ; but some crystals are very 

 complex. 



Obs. Spliene occurs mostly in disseminated crystals in 

 granite, gneiss, mica slate, syenyte, or granular limestone. 

 It is usually associated with pyroxene and scapolite, and 

 often with graphite. It has been found in volcanic rocks. 

 The crystals are commonly ^ to J an inch long ; but are 

 sometimes 2 or more inches in length. 



Foreign localities are Arendal in Norway ; at St. Gothard 

 and Mont Blanc ; in Argyleshire and Galloway in Great 

 Britain. Occurs in Canada, at Grenville and elsewhere ; 

 New York, at Roger's Rock, on Lake George ; with graphite 



