fO TABLE SPAR. 



Analysis, by Svanherg : 



Silica 



Alumina 



Magnesia 



Protoxide of iron 



Protoxide of manganese 



Potash 



Fluoride of magnesium 



Water , . . . 



. 35-76 

 . 13-03 



. 29-27 

 . 6-34 

 . 1-64 

 . 2-07 

 . 1-10 

 . 11-76 



100-97 



Table Spak, \ See Wollas- 



Tabulak Spar, Phillips. § tonite. 

 Tabular Quartz. Thin plates of 

 Quartz, either arranged parallel to or cross- 

 ing one another, so as to form open cells. 



Tachyaphaltite, Berlin. Probably an 

 altered Zircon. Occurs in short thick 

 prisms of a dark reddish-brown colour, 

 with a lustre varying from submetallic to 

 vitreous. Subtranslucent. Streak dirty yel- 

 low. Fracture conchoidal. H. 5-5. S.G. 3-6. 

 Analysis, by Berlin : 



Silica 34-58 



Zirconia . . . .38-96 

 Peroxide of iron . . . 3-72 

 Alumina . . . .1-85 

 Thoria? . . . .12 32 

 Water .... 8-49 



99-92 



BB infusible, but becomes dirty white: 

 with borax dissolves with difficulty. 



Locality, tvrageroe in Norway, in granite 

 veins traversing gneiss. 



Name. From ra-xv;, quick, and «.<^cckTo;^ 

 springing off ; in allusion to the readiness 

 with which the mineral flies from thegangue 

 when struck. 



Tachydrite, Rammelsherg. An ex- 

 tremely deliquescent salt, resembling Car- 

 nallite, occurring in round masses in com- 

 pact Anhydrite. Colour yellow. Trans- 

 parent or translucent. Cleavable in two 

 directions. 



Comp. 2MgCl + CaCl + 12H. 



Analysis (mean of two) -. 



Calcium .... 7-46 

 Magnesium . . .9-51 



Chlorine .... 40-34 

 Water .... 42-69 



100-00 



Locality. Stassfurt. 



Tachylite, Breithaupt, Mohs. The name 

 proposed by Breithaupt for a kind of Iso- 

 pyre. Amorphous-massive or in plates. 

 Colour velvet-brown or black. Opaque. 



TALC. 



Lustre vitreous to greasy. Streak dark* 

 grev. Fracture conchoidal. H. 6*5. S.G. 

 2-5 *to 2-7. 



Comp. (R3 + Al) Si, or 2(K, Na, Ca, Mg, 



Mn, Fe) (Fe, Al,) Si*. 



Analysis, from Sasebiihl, by Sclinedev 



mann : 



Silica 55-74 



Alumina .... 12-40 

 Protoxide of iron . . 13-06 



Lime 7-28 



Magnesia .... 5-92 



Soda 3-88 



Potash .... 0-60 



Protoxide of manganese . 0-19 

 Water ...... 2-73 



101-80 



BB fuses very readily to an opaque glass. 



Decomposed completely by concentrated 

 muriatic acid in the cold. 



Localities. On the Sasebiihl near Drans- 

 feld, and at Hollengrund near Miinden ; 

 forming small masses in basalt and wacke. 

 The Vogelsgebirge in igneous rocks. See 

 Sideromelan. 



Name. From T«%y?, quick, and Ai!&;, to fuse. 



Brit. Mus., Case 33. 



Tachylite is stated by Xaumann & Ram- 

 melsherg to be a basaltic glass, and, con - 

 sequently, to have no definite composition. 



Tafelspath, Stxttz. Table-spar. See 



WOLLASTONITE. 



Tagilite, Hermann. Occurs in fungoid or 

 botryoidal masses, with a rough and earthy 

 surface. Structure radiating - fibrous and 

 earthy. Colour emerald.-green, or mountain- 

 green when weathered. H. 3. S.G. 4 35. 



Comp. (Libethenite + 2H), or phosphate 



of copper: =Cu4p + 3H, with a trace of 



arsenic. 



Analysis, by Hermann : 



Phosphoric acid . . . 27*70 



Oxide of copper . . . 61*80 



Water . . . .10-50 



100-00 

 T^ocality. Nijni-Taguilsk, in the Ural ; 

 on Brown Iron Ore. The Mercedes Mine, 

 about 20 miles E. of Coquimbo, in Chili, 

 forming stellated and fibrous masses in 

 Bi-own Iron Ore. 

 Brit. Mus., Case 57. 



Talc, Haiiy. Occurs rarely in rectan- 

 gular prisms, and in thin hexagonal plates, 

 with a perfect basal cleavage. Generally 

 massive, foliated, and granular ; also slaty 

 and earthy. Colour apple-^green to silver- 



