SMOKE QUARTZ. 



less ; sometimes grey, blue, yellow, green or 

 brown. Transparent to translucent or 

 opaque. Lustre vitreous, inclining to ada- 

 mantine. Streak white. Brittle. Fracture 

 uneven. Becomes phosphorescent when 

 rubbed, and electric by heat. H. 5. S.G. 

 3-16 to 3-38. 



Fig. 393. 



Fig. 394. 



Comp. Silicate of zinc, or 2Zn5 Si + H: 



oxide of zinc 67*4, silica 25*1, water 7'5. 



Analysis, from Limburg, by Berzelius ; 



Oxide of zinc . . . 66-37 



Silica . . . . . 26-23 



Water . . . .7-40 



100-00 



BB decrepitates ; does not fuse, but swells 

 up when strongly ignited; intumesces 

 slightly with carbonate of soda, but does 

 not dissolve in it, and gives, though not 

 readily, a deposit of Zinc-oxide. 



Dissolves readily in acids, with separation 

 of a siliceous jelly; dissolves for the most 

 part in caustic potash. 



Localities. — JEjiplish. Cumberland, at 

 Eoughten Gill, and Alston Moor. Derby- 

 shire: at the Rutland Mine, ^^.394; near 

 Matlock, at IMasson Hill and Castleton. 

 Mendip Hills, Somersetshire. — TFehh. Near 

 Holywell, in Flintshire. — Scotch, Lead- 

 hills, in Lanarkshire. — Foreign. Nert- 

 schinsk, in Siberia. Aix-la-Chapelle. Rai- 

 bel, in Carinthia. Tarnowitz, in Silesia. 

 Olkucz, Miedziana-Gora, in Poland. Rez- 

 banya, Schemnitz, in Hungary. Jefferson 

 CO., Missouri, Austin's Mines, Wythe co., 

 Virginia. 



Name. After the chemist, Smithson. 



Brit. Mus., Case 26. 



M.P.G. Principal Floor, Wall-case 12 

 (British). 



Smoke Quartz, Bahewell, or Smoky 

 Quartz. Has a brownish, smoke coloured 

 tint, and comprises the wine-yellow and 

 clove-brown crystals, which are the true 

 Cairngorm. It is found in Scotland, 

 Bohemia, Pennsylvania, Brazil, &c. See 

 Cairngorm, False Topaz, Morion, and 

 TopAziNE Quartz. 



Brit. Mus., Case 20. 



31. P. G. Horse-shoe Case, ISTos 507, 508. 



Smut, or Mucks. Names given by 



SODALITE. 851 



Derbyshire miners to bad, soft coal, con- 

 taining much earthy matter, found in the 

 immediate neighbourhood of faults, or de- 

 composed near the surface by the influence 

 of atmospheric causes. 



SoAPSTONE, Nicol, Phillips. See Sapo- 

 NiTE. The name is also applied to Steatite 

 (which see). 



Soda Alum, Phillips, Thomson. Occurs in 

 white fibrous crusts or masses, exhibiting a 

 glossy aspect internally. H. 2 to 3. S.G. 

 1-88. 



Resembles potash-alum in taste, but is 

 more soluble in water. 



Comp. S Na + Al S^ 24H, or sulphate of 

 soda 15-5, sulphate of alumina 37-4, water 

 47-1 = 100. 



Analysis, from Mendoza, by Thomson : 

 Sulphuric acid . . . 37*70 

 Alumina . , . .12 00 



Soda 7-96 



Water . . . .41-96 



99-62 



Localities. — St. Juan, near Mendoza, in 

 S. America. Near the Solfatara, Naples. 

 Island of Milo. 



Brit. Mus., Case 55. 



Soda cjiiabazite. See Gmelinite. * 



Soda copperas. A mineral from Bo- 

 hemia, related to Jarosite. 



Analysis, by Scheerer : 



Sulphuric acid . . . 32-42 ' 



Protoxide of iron . . 49-37 



Soda 4-03 



Water .... 13-13 



98-95 



Soda mesotype. See Natrolite. 



Soda nitre. See Nitratine. 



Soda spodumene. See Oligoclase. 



Soda table-spar, Thomson. A variety 

 of Pectolite, met with at Kilsyth, in Stir- 

 lingshire. 



Soda • Wallastonite, Thomson. See 

 Pectolite. 



SoDAiTE. See Ekebergite. 



SoDALiTE, Phillips,Thomso7i, Haiiy, Nicol. 

 Cubical. Generally occurs cr^'stallized in 



rhombic dodecahedrons, with a dodecahedral 

 cleavage : also massive. Colour white, grey, 



