402 DETERMINATION OF MINERALS. 



CYANITE, p. 286. H.=o-7 (greatest on extremities of crystals); 



Gr. =3*6 ; in long or short prismatic crystallizations, often bladed 



prisms ; pale bine to white and gray. 

 LEUCITE, p. 271. H. =5'5-6 ; G.=2*5 ; white, gyh ; often in trapezo- 



hedral crystals. 



b. Not giving a blue or reddish color with cobalt solution ; H. = 



8 to 5. 



SPINEL, p. 194. H.=8 ; G. =3*5 4*1 ; in octahedrons of red, green- 

 ish, gray, black colors. Gahnite is similar, but with borax on coal, 

 gives reaction for zinc. 



BERYL, p. 252. H. =7-5-8; G. =2-6-2*7 ; always in hexagonal 

 prisms ; pale bluish and yellowish green, to emerald-green, also 

 resin yellow and white, no distinct cleavage. 



ZIRCON, p. 259. H. = 7*5 ; Gr. =4-4*75 ; dimetric, and often in square 

 prisms ; lustre adamantine ; brown, grav. 



STAUROLITE, p. 291. H.=7; G.=3*4-3*8 ; in prisms of 123% 

 and often in cruciform twins ; no distinct cleavage ; brown, black, 

 gray. 



QUARTZ, p. 233. H.=7; G.=2*6 ; often in hexagonal crystals 

 with pyramidal terminations ; of various shades of color. Opal, 

 p. 239, is in part anhydrous. 



IVZONAZITE, p. 203.' H.=5-55; G. =4*9-5*3; in small brown im- 

 bedded monoclinic crystals, with perfect basal cleavage ; B.B. flame 

 bluish-green when moistened with sulph. acid. 



RUTILE, p. 162. H.=6-6 5; G. =4*15-4*25 * dimetric; reddish- 

 browD to brownish-red, green, black ; B.B. reaction for titanium. 

 Brookite and Octahedrite, p. 163, are similar, except in crystal- 

 line forms, and Gr. in brookite 40-4*25, in octahedrite 3-8-3'95. 



PEROFSKITE, p. 163. H.=5*5 ; G. =4-4-1 ; yellowish, brown, 

 black : cubic and octahedral forms ; B.B. reaction for titanic acid. 



ENSTATITE, p. 244. H. =5*5 ; G. =3 1-3 "3 ; in prismatic and fibrous 

 forms with I/\ 7=88' 16', also foliated ; whitish, grayish, brown. 

 AnthophyV.ite is similar, but 2X7=125°, and it fuses on the edges 

 with great difficulty. 



Iolite, apatite, sche elite, enclose, fuse with much difficulty, and 

 euclase gives some water in closed tube when highly ignited. 



2. FUSIBLE WITH LITTLE OR MUCH DIFFICULTY. 

 A. Gelatinize and afford a Stiff Jelly. 



a. Hydrous ; fuse easily. 



DATOLITE, p. 289. H. =5-5-5; G. =2*8-3; white, greenish, yel- 

 lowish ; crystals glassy, stout, sometimes massive and porcellanous, 

 never fibrous ; B.B. fuses easilv, reaction for boron. 



NATROLITE, p. 299. H. = 5-5*5 ; G. =2-3-2 4 ; in slender rhombic 

 prisms, and divergent columnar ; white, y wh, rdh, red ; B.B. fuses 

 verv easilv. 



SCOLECITE, p. 299. H.=5-5o ; G. =2*16-2*4; crvst. much like 



