290 DESCRIPTIONS OF MINERALS. 
Titanite.—Sphene. 
Monoclinic. In very oblique rhombic prisms ; the lateral 
faces making angles often of 76° 7’, 118° 81’ (ZA Z), 186° 12’ 
I: 2. 
LON 
(2A2), or 133° 52’. 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. ‘I'ransparent to opaque. H.=5- 
5°56 G.2=3°2-3-6: 
Composition. CaTiO; 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 sphene. ‘The name sphene alludes 
to the wedge-shaped crystals, and is from the Greek sphen, 
wedge. (Greenovite is a variety colored rose-red by manga- 
nese. 
Diff. The thin wedge-like form of the crystals, in general, 
readily distinguish this species; but some crystals are very 
complex. 
Obs. Sphene 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 4 to $ 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 



