146 GABRONITE, 



a. 



Gaeronite, Beudant, Dufrenoy. A variety 

 of Scapolite, found only at Arendal, in amor- 

 phous masses, with a compact or slightly 

 lamellar texture. Colour stone-yellow. Lus- 

 tre greas3^ S.G. 2-74, 



Name. From its resemblance in colour 

 to the rock called Gabbro. 



Gadohmite, Jiimeson, Fhillips, Haily, 

 Mohs. Oblique : when crj^stallized, usually 

 in imperfect, oblique rhombic prisms, the 

 primary form. Colour iron-black ; dull ex- 

 ternally, internally black and shining. Lus 

 tre vitreous, inclining to resinous. Opaque 

 or feebly translucent at the edges, when it 

 appears blackish-green. Streak greyish- 

 green. Brittle. Fracture conchoidal. No 

 distinct cleavage. H, 6-5 to 7. S.G. 4-097 

 to 4-226. 



Fig, 200. 



Comp. Y5 Si, but in all varieties of Gado- 

 linite, a portion of the yttria is replaced by 

 several other bases. 



Analysis, from Ytterby, by Berlin : 



Silica 24-85 



Glucina .... 4-80 



Yttria 51-46 



Oxide of cerium, with oxide 



of lanthanum . . . 5*24 

 Protoxide of iron . , . 13-01 



Lime 0-50 



Magnesia and protoxide of 

 manganese . . .1*11 



100-97 



BB the Karafvet variety decrepitates and 

 s fuses, when strongly heated, to an opaque 

 ■pearl-grey or reddish glass; that from 

 Ytterby exhibits a vivid glow, and loses its 

 colour, but does not fuse. With borax all the 

 varieties melt readily to a globule, more or 

 less tinged with iron. 



Gelatinises in muriatic acid. 



Localities. — British. In one single instance 

 only, in the county of Galway, in trap. — 

 Foreign. It occurs principally in Sweden, at 

 the quarries of Karafvet and Finbo,nearFah- 

 lun, where, as well as at Ytterby, near Stock- 

 holm, it is found indistinctly crystallized, 



GALEXA. 



and in amorphous masses, which are often 

 encircled with a yellow crust, and are im- 

 bedded in coarse-grained granite. It has 

 also been been met with at Disko, in Green- 

 land; in granite, in Ceylon ; at Finbo and 

 Broddbo ; and at Krageroe and Hitteroe, in 

 the southern part of Norway. 



Name. After the Russian chemist, Gra- 

 dolin, by whom it was first noticed in 1794. 

 He discovered in it the new earth Yttria. 



Brit. Mus., Case 38. 



Gagates, Dinscorides. The name by 

 which Jet was known to the ancients. It 

 was so called from Gagis, a town in Lycia, 

 where it was said to have been originally 

 found. 



Gahnite, Beudant, Hausmann. A name 

 for Automalite, after the discoverer Gahn. 



See AUTOMALITK. 



Galactite, Haidinger. Occurs radiating 

 and compact at the Campsie Hills, Stirling- 

 shire, and in long acicular crystals, with 

 Prehnite, at Bishoptown, Renfrewshire. Re- 

 cent analyses, by Heddle and Kenngott, 

 have proved it to be Natrolite. 



Name. From ya-^a, yot.\a.y,io? ^ milk, because 

 when immersed or triturated in water, it 

 gives the colour of milk. 



Galapectite, Dufrenoy. A variety of 

 Halloysite occurring in greenish-white 

 masses which are opaline in places, and 

 analogous in that respect to certain kinds of 

 opaline Quartz. Slightly hard. May be 

 cut with a knife. Fracture conchoidal. 



Galena, Kirwan, Brooke §• Miller, 

 Phillips, Greg ^ Lettsom ; GaljeNE, Beu- 

 dant; Galrnit, v. Kobell; La GaleNE 

 Commune, Brochant. Cubical. Occurs crys- 

 tallized in the cube, octahedron, and in 



Fig. 201. 



Fig. 202. 



^ 



Fig. 203. 



Fig. 204. 



numerous combinations of these with planes 

 of other iigures : also in amorphous masses 

 Avith a lamellar structure ; frequently granu- 

 lar ; sometimes almost compact, yielding a 

 flat-conchoidal fracture, and presenting 



