418 ZIRCON. 



There are two varieties, one (a) contain- 

 ing copper, and the other (b) without cop- 

 per. The former is of a fine sulphur-yellow 

 colour, and occurs in delicate needles, or 

 acicular rosettes, or warty crasts ; the latter 

 lemon- to orange-j^'ellow. 



Comp. Of copper variety Cu S + ^ S^ + 

 12H; of variety without copper ^3 8^ + 

 12H. 



Analysis, from Joachimsthal, by Vogl : 



(«) (&) 

 Sulphuric acid . 17-36 13-06 

 Peroxide of ura- 

 nium . . . 62-04 67-85 

 Peroxide of iron . — 0*17 

 Oxide of copper . 5-20 — 

 Lime . . . — 0*67 

 Water . . . 15-23 17-70 



99-84 99-39 



55 becomes orange-yellow when heated 

 gently. Tn the reducing flame changes to 

 green, but does not fuse. 



Localities. — English. Cornwall : Calling- 

 ton ; Carharrack ; Withiel Iron-mine ; Huel 

 lEdward ; Huel Buller ; near St. Michael's 

 Mount, coating Mica, on a quartzose rock. 

 • — Foreign. Joachimsthal, in Bohemia. Sym- 

 phorien, in France. The felspar quarry, near 

 Middletown, Connecticut, U.S. 



Name. In honour of Zippe, Professor of 

 Mineralogy in Prague. 



Zircon, Werner, Dana, Phillips, Nicol, 

 Brooke 8f Miller, Hauy, Hausmann, Greg §■ 

 Lettsom. Pyramidal: primary form an 

 obtuse octahedron, with a square base. 

 Occurs in crystals bearing a remarkable 

 resemblance to those of oxide of tin ( Cassi- 

 terite) with which it is isomorphous; also in 

 rounded grains. Colour red, brown, yellow, 

 green or grey ; rarely white. Transparent 

 ito opaque. Doubly refractive. Lustre more 

 or less adamantine. Streak white. Fracture 

 conchoidal and brilliant. H. 7*5. S.G. 4 

 to 4-75. 



,Fig. 472. 



Fig. 473. 



Comp. Silicate of zirconia, or :Z-r Si = 

 zirconia 66-23, silica 33-77 = 103. 



ZIRCONITE. 



Analysis, from Ceylon, by Vauquelin : 



Zirconia . . . 64*5 



Silica 32-6 



Peroxide of iron . . .2-0 



99-1 



BB loses colour but does not fuse. In a 

 large quantity of borax, dissolves with 

 diflicult}^ and forms a transparent glass; 

 wiih a smaller quantity forms a turbid glass. 

 Does not dissolve to any perceptible extent 

 in microcosmic salt or carbonate of soda. 

 Zircon may be fused with potash, lime, or 

 oxide of lead. 



Not decomposed by acids — even by 

 muriatic acid — hot oil of vitriol, however, 

 acts slightly on it. 



Localities. — Scotch. Strontian, Argyle- 

 shire; fg. 472. Isle of Harris, ,fig. 473. 

 Sutherlandshire. — Irish. Croghan Kinshela 

 mountain, in the auriferous streams. — Fo- 

 reign. Kitiksut, in Greenland. Norway, 

 along the ChristianiaiQord, between Stavarn 

 and Hackedalen. Sweden. The Sau-Alp, 

 in Carinthia. The Siebengebirge. Expailly, 

 in Auvergne. Vicenza, in Italy. Vesuvius, 

 in ejected blocks. Assuan, in Upper Egypt. 

 Sonae stones of very fine colour and trans- 

 parehc}^" constituting veritable gems," have 

 been obtained by Sir William E. Logan, 

 in Canada ; they occur in the crystalline 

 limestone of the Laurentian series, at 

 Grenville Township, Argenteuil co., C. E. 



Name. From the Arabic word Zerk, 

 signifying a precious stone. 



Brit. Mus., Case 26. 



3LF. G. Horse-shoe Case, Nos. 845, 

 846, 850 to 852. 



Zircon is divided into three varieties ; 1st, 

 the colourless or slightly smoky or Jargoon; 

 2nd, the bright red or Hyacinth ; and 3rd, 

 the greyish or, brownish, called Zirconite. 

 See also Erdmannite and Ostranite. 



Zircons with the same crystalline form, 

 the same external characters, and in every 

 respect precisely identical with the Zircons 

 of Somma (Vesuvius) have been recently 

 obtained artificially by Mons. Henri Sainte- 

 Claire Deville, by' passing fluoride of sili- 

 cium over Zirconia at a red heat. Mons. 

 Deville believes that it may be inferred, 

 Avith nearly absolute certainty, that the 

 Zircon has been formed by igneous agency, 

 from the small quantities of Fluor which are 

 present in the metamorphic rocks in which 

 it occurs. 



Zirconite. The name applied to the 

 greyish or reddish-brown and nearly opaque 

 varieties of Zircon. 



