THIERSCHITE. 



Magnesia 

 Soda . 

 Water . 



. 37-65 

 . 2-85 

 . 10-65 



lOO'OO 

 BB swells up more than Pyrophyllite and 

 Yermiculite. 

 Scarcely acted on by muriatic acid. 

 Locality. Hoponsuo, near Pitkaranda, in 

 Finland. 



Thiekschite. Oxalate of lime, occur- 

 ring in the form of a thin, greyish, opaline 

 incrustation, on the marble of the Parthenon 

 at Athens. 



Thiosaurite, Genth. A A-ariety of Anor- 

 thite from Iceland, of a white to a greyish 

 colour. H. 6. S.G. 2-688. 

 Analysis, bv Genth: 



Silica / . . . . 48-36 

 Alumina .... 30-59 

 Peroxide of iron . . .1-37 

 Magnesia .... 0-97 

 Protoxide of manganese . trace 



Lime 17-16 



Soda 1-13 



Potash , . , .0 62 



100-20 



The name is derived from that of the 

 locality where the mineral is found — the 

 Plain of Thiorsa. 



Thomaite, Dana. A prismatic form of 

 carbonate of iron, from the Siebengebirge, in 

 Rhenish Prussia. S.G. 3-10. 



It was named after Professor Thoma, of 

 Wiesbaden. 



TllOMSONiT, Haidinger, v. Kobell ; or 

 Thomsonite, Brooke, Dana, Grey ^Lettsom. 

 Rhombic : primary form a right rhombic 

 prism, with cleavage parallel to its side. 

 It generally occurs in masses with a colum- 

 nar or radiated structure, in the occasional 

 cavities of which indistinct crA'stals may be 

 observed. Colourless or snow-white: im- 

 pure varieties brown. Translucent; in small 

 fragments transparent. Lustre vitreous, 

 inclining to pearly. Streak white. Brittle. 

 Fracture uneven. H. 5 to 5-5. S.G. 2 35 to 

 2-4. 



^P^ 



Fig. 432. 



Fig. 433. 



Comp. (Ca, Na)3 Si + 3A1 Si + 7H = silica 

 37-4, alumina 31-8, lime 13-0, soda 4*8, 

 water 13-0 = 100. 



THORITE. 

 Analysis, from the Kilpatrick HillS; 

 Berzelius : 

 Silica . 

 Alumina 



by 



Lime 

 Soda 

 Water 



38-30 

 30-70 

 13-54 

 4-53 

 13-10 



100-17 



BB swells up, becomes opaque, and fuses 

 at the edges to a white enamel. 



Yields a jelly with acids. 



Localities. — Scotch. St. Cyrus and Ar- 

 buthnot, in Aberdeenshire, in basalt. In 

 the neighbourhood of Kilpatrick and Dum- 

 barton, Dumbartonshire (Jigs. 432, 433). 

 Kilmalcolm and Port Glasgow, in Renfrew- 

 shire. — Irish. Near the Giant's Causeway. 

 Magee Island. 



Name. After Dr. Thomson, Professor of 

 Chemistry in the University of Glasgow. 



Brit. Mus., Case 27. 



31. P. G. Horse-shoe Case, No. 1175. 



Thon, Werner. Clay. 



Thoneisenstein, Werner. Clay Iron- 

 stone. 



Thonerde. Alumina. 



Thonerde Schwefelsaure. See Al- 



UNOGENE. 



Thorite, Berzelius, Dana. In pyramidal 

 prisms: generally massive and compact. 

 Ismorphous with Zircon (E. Zschau). Co- 

 lour black, reddish-brown, or orange-yellow 

 {Orangite). Opaque; in thin splinters trans- 

 parent. Lusti-e of fresh fracture vitreous. 

 Streak dark brown, or pale orange. Easily 

 frangible. Fracture conchoidal. H, 4-5 to 

 5. S.G. 4-63 to 4-8. 



Comp. Silicate of thoria, or Th^ Si + 



3H = thoria 73-7, silica 16-5, water 9-8 = 100. 



Analysis, by Berzelius : 





Thoria . • . . 



. 57-91 



Silica . 



. 18-98 



Peroxide of iron . 



. 3-40 



Peroxide of manganese 



. 2-39 



Alumina 



. 0-06 



Peroxide of uranium 



. 1-61 



Oxide of tin 



. 01 



Oxide of lead 



. 0-80 



Lime . 



. 2-58 



Magnesia 



. 0-36 



Soda . 



. 0-10 



Potash 



. 0-24 



Water . 



. 9-50 



Undecomposed mineral 



. 1-70 



Loss 



. 0-49 



100-13 



