STLVIN. 



and verv sectile. Brittle. Fracture semi- 



coqchoickl. H. 1-5 to 2. S.G. 7'99 to 8-28. 

 Comp. Telluride of gold and silver, or 



Ag Te4 + Au Te3 = silver 13-8, gold 20-5, 



tellurium 59'7 = 100. 



Analysis, from Offenbanya, by Petz : 

 Silver . . . . \ 11-47 



Gold 21-97 



Tellurium .... 39-97 



Lead 0-25 



Copper 0-76 



Antimony . . . . O'oS 



100-00 



BB on cbarcoal fuses, emitting a slightly 

 acid odour, covers the charcoal with a Avhite 

 deposit, and is reduced to a dark grey me- 

 tallic globule, which is converted, by long 

 blowing, into a pale yellow alloy of gold 

 and silver, exhibiting incandescence at the 

 moment of soliditication. — (^Berzellus.) 



Dissolves in aqua-regia, with separation of 

 chloride of silver, and forms a solution Avhich 

 gives a white precipitate on dilution with 

 water. 



Localities. Offenbanya, in Transylvania 

 (Graphic Tellurium of Phillips), associated 

 with Gold, in narrow veins traversing por- 

 phvry. Nagvag, in Transvlvania {Fellmo 

 Tellurium of" Phillips). Gold Hill, North 

 Carolina, U. S. 



Brit. Mus., Case 3. 



Sylvanite constitutes a valuable ore of 

 gold and silver. 



Sylvin, Nicol, Vogel. Sylvine, Dana. 

 Sylvyne, Beudant, Phillips. Cubical. Oc- 

 curs crystallized in cubes, with a. cleavage 

 parallel to the faces of the cube. Colourless, 

 or white. Lustre vitreous. Soluble. Tastes 

 like Common Salt. S.G. 1-91 to IQo.^ 



Comp. Chloride of potassium, or K Cl = 

 potash 52-6, chlorine 47-4 = 100. 



Decrepitates when heated, fuses at a low 

 red heat, volatilizes at a higher temperature 

 unchanged. It is somewhat more volatile 

 than Common Salt ; in a covered crucible, 

 it may be kept in a state of fusion without 

 loss ; in open vessels, it volatilizes gra- 

 dually in the constantly renewed current of 

 air. — {H. Rose.) 



Localities. The mines of Hallein in 

 Salzburg, and Berchtesgaden in Bavaria, 

 with Common Salt ( Vogel). Vesuvius, in a 

 state of sublimation about the fumaroles. — 

 (^Smithson). 



Name. The name Sylvine was given to 

 this mineral in consequence of its being the 

 digestive salt of Sylvius de la Boe. 



Symplesite, Breithaupt. Oblique. Oc- 



TABERGITE. 369 



curs in very minute prismatic crystals, and , 

 also in acicular radiations. Colour pale 

 indigo, inclining to celandine-green. Trans- 

 parent to translucent. Lustre vitreous ; of 

 cleavage-planes pearlv. Streak bluish-white. 

 Rather sectile. IL 2"o. S.G, 2-957. 



Comp. Hydrated arseniate of protoxide 



of iron, or 3Fe As^ + 8H. 



BB gives off' strong arsenical odours, be- 

 comes black and magnetic, but does not fuse. 



Locality. Klein- Friesa, near Lobenstein, in 

 Reuss, with Sparry Iron and Cobaltic Pyrites. 



Name. From eruiM'^Kr.a-ia.ii^, to draio close 

 together. 



T. 



Tabasheer. a siliceous concretion, 

 bearing some resemblance to Hydrophane, 

 found in the interior of the stem of the large 

 Indian bamboo. It is imperfectly trans- 

 parent, and sometimes altogether opaque, 

 bur, -when immersed in water, it gives out a 

 quantity of air-bubbles, and becomes more 

 transparent, returning to its original opacity 

 on exposure to the air. S.G. 2-059 to 2*412 

 (Brewster) when completely saturated with 

 Avater, when its weight is more than doubled. 

 Analysis : 



Silica 96-94 



Potash and lime . . . 0-13 

 Water . . . . , 2-93 

 Organic matter . . . trace 



100-00 

 Silica enters into the composition of the 

 stem of the Indian bamboo, in the same 

 way that it does into that of ordinary wheat- 

 straw. In the former case, the silica is 

 found to occur in different quantities in the 

 different parts of the cane. Thus, the pith, 

 contains 0*448 per cent.,the inner wood much, 

 less, and the greater proportion is found in 

 the external wood. Reasoning on this fact, 

 the formation of Tabasheer is explained by 

 Mons. Guibourt in the following manner: 

 " At the time when the straw is developed, 

 the outer wood has no longer any necessity 

 for silica, Avhich is carried inwards and de- 

 posited in the cavity of the straw," 



The Orientals regard Tabasheer as one of 

 the most valuable of medicines. In India it 

 is called Vedroo-paloo (bamboo - milk), 

 Vedroo-carpooram (bamboo - camphor), and 

 Manzil-upoo (^bamboo -salt). 



Tabergite, Hose. The name given to 

 the Pyrosclerite of Taberg, in Wermlaud. 



B B 



