124 ELECTRUM. 



lias been applied to Smithsonite, or tlie 

 siliceous oxide of zinc, in consequence of its 

 becoming electric b}^ heat, and sometimes 

 by friction. 



Electhum, Klaproth. A natural alloy 

 of gold and silver in the proportion of two 

 of gold to one of silver, or Gold G5, and 

 Silver 36 = 100. It is distinguished by its 

 silver-white colour. S.G. 14 to 17. 



BB fuses to a more or less pale-yellow 

 globule. 



Localities. It occurs in tabular crystals 

 and imperfect cubes at Schlangenberg, in 

 Siberia ; also at Kongsberg, in Norway ; in 

 Transylvania ; near Glariposa in California, 

 and in other mining districts. 

 Brit. Mus., Case 3. 



Elhuyazite, Fuchs. A variety of Allo- 

 phane. 



Eliasite. a mineral near to Pitch- 

 blende, but differing widely from it in its 

 lower specific gravity and large proportion 

 of water. It occurs in large flattened 

 pieces, sometimes half an inch thick, of a 

 dull reddish-brown colour, approaching to 

 hyacinth-red at the edges. Lustre greasy 

 to subvitreous. Subtranslucent. Streak 

 dull, wax-vellow to orange. H. 3-5. S.G. 

 4-086 to 4-237. 



Analysis, by F. Ragsky i 



Peroxide of uranium . .61-33 

 Peroxide of iron . . . 6-63 

 Alumina .... 1'17 

 Protoxide of iron . . . 1-09 



Silica 5-13 



Lime 3-09 



Magnesia . . . .2-20 

 Oxide of lead . . . 4-62 

 Carbonic acid . . . 2*52 

 Phosphoric acid . . .0-84 



Water 10-68 



Arsenic .... trace 



99-30 



BB like Pitchblende. 



Decomposed by muriatic acid. 



Locality. Tiie Eiias Mine, Joachimstahl ; 

 with Fluor, Dolomite, Quartz, &c. 



Elie Ruby. A variety of Pyrope found 

 In trap-tufa at EUe in Fife. 



Analysis by Connell : 



Silica 42-80 



Alumina .... 2865 

 Peroxide of iron . . .9-3 

 Protoxide of manganese . 0-25 

 Magnesia .... 10-67 



Lime 4-78 



Chromic acid . , . trace 



96-46 



EMER4LD. 



Ellagite, Nordenshiold. Colour yellow, 

 yellowish- brown, to yellowish-red. Opaque 

 or feebly translucent. Lustre of cleavage- 

 surface pearly, shining. Streak white. 



Comp. Ca3 Si* + ^1 Si + 12 H. 



Locality. Aoland, in Finland. 



Embolite, Breithaupt. Cubical : in cubes, 

 and cubo - octahedrons. Colour varying 

 from asparagus- to gre3'ish-green. Lustre 

 resinous. H. 1 to 1-5. S.G. 5-31 to 5-81. 



Comp. Chlorobromide of silver, or 3 Ag 

 CI + 2 A g Br = chlorine 13-2, bromine 19-8, 

 silver 67-0 = 100-0. 



Analysis, mean of three, by Domeyko : 

 Chloride of silver . . . 51-6 

 Bromide of silver . . . 48-4 



100^ 

 Localities. Abundant in Chili, at Quillota 

 and Chaviarcillo ; found also at Eulalia, in 

 Chihuahua, Mexico ; and at Colula, in Hon- 

 duras. 



It is stated by Domeyko, that " the chloro- 

 bromides vai-y in colour from greyish-green 

 or yellow to asparagus- and pistachio-green. 

 In general the specimens that have a yellow 

 colour have more bromine, and consequently 

 less silver, than those of a grey or pearly- 

 green colour." 



Kmbrithite, Brochant. See Boulange- 



RITE. 



Emerald. Hexagonal. Colour green, 

 passing into light blue, impure yellow, and 

 white for the Beryl. Lustre vitreous, some- 

 times resinous. Transparent to subtranslu- 

 cent. Streak white. Brittle. Fracture con- 

 choidal, uneven. H. 7-5 to 8 0. S.G. 267 

 to 2-732. 



Fig. 174. 



ifl" 



Fig. 175. 



Comp. » + Al + 4 Si = (B + Al) Si^ = glu- 

 cina 14-1, alumina 19-0, silica 66-9 = 1000. 



Analysis of Emerald of Muzo : 



Silica 680 



Alumina .... 18'1 



Glucina 12-2 



Magnesia .... 0-9 



Soda 0-6 



Tantalic acid .... trace 



99-8 

 In the above analysis, by M. Lewy, traces 

 of chromium are reckoned with the mag- 

 nesia, and perhaps there is a little Titanic 

 acid with the alumina. In previous trials, 



