S68 PHYSIOGRAPHY. CLASS ir. 



Disthene-spar, into a continuous mass with parallel axes. 

 Mr ROSE first observed that the perfect planes of cleav- 

 age of the two crystals always coincide. Less perfect 

 are the varieties from Sebes in Transylvania. Twin-crys- 

 tals occur at St Jago de Compostella in Spain, and Oporto 

 in Portugal. There occur likewise several varieties in 

 France, in Aberdeenshire, and several of the isles in Scot- 

 land ; in Brazil; and near Philadelphia hi North America. 



GENUS XII. ZIRCON. 



1. PYBAMIDAL ZIRCON. 



Pyramidal Zircon. JAM. Syst. Vol. I. p. 29. Man. p. 230. 

 Zircon. PHJLL. p. 90. Zirkon. Hiazinth. WERX. 

 Hoffm. H. B. I. S. 396, 40?. Zirkon. HAUSM. II. 

 S. 618. Zirkon. LEONH. S. 391. Zircon. HAUV. 

 Traite, T. II. p. 465. Tabl. comp. p. 28. Traite,, 

 2de Ed. T. II. p. 291. 



Fundamental form. Isosceles four-sided pyramid. 

 P = 123 \W, 84 2(X. Vol. I. Fig. a R. G. 



a = V 0-8204. 



Simple forms. P oo ; P 1 (t) = 135 10', 

 65 17' ; P (P), Expailiy, France ; P + 2 = 103 

 31', 122 12' ; -;- P + 3 (u) = 96*51', 139 35' ; 

 P + oo (/) ; [P + oo] (*) ; (P) 3 (a) = 132 43', 

 147 3', 127 27'; (P) 4 (y) ; (P) 5 (z). 

 Char, of Comb. Pyramidal. 



Combinations. 1. P. P + oo. St Gothard, Swit- 

 zerland. 



2. P. [P + OB]. Sim. Fig. 97. Ceylon. 



3. P. (P) 5 . P + oo. [P -f- ] Ohlapian. 



4. P. (P)'. ^-j P + 3. P + a. [P + oc]. 

 Vol. I. Fig. 68. Frederiksvarn, Norway. 



