522 



MEASUREMENTS OF CRYSTALS. 



COPPER PYRITES. Figs. 505 to 508 inclusive. 

 Page 423. 

 Fig. 505. The primary, an octahedron 

 with a square base. 



P onP' 125°30' 



P onPorP'onP' ... 102 30 

 Fig. 506. 



lonl 71°10' 



Fig. 507. A twin, composed of about 

 equal parts of an octahedron, one 

 half of which is turned round. St. 

 Lawrence county. 

 Fig. 508. 



Pone 140O30' 



AZURITE. Fig. 509. P.ige 42G. 



Fig. 509. The primary, an oblique rhom- 

 bic prism. 



MonM' 98=50' 



M or M'onP 91 30 



ANATASE. Fig. 510. Page 408. 



Fig. 510. The primary, an octahedron 

 with a square base. 



P onP' 136°47' 



P onP or P'onP' ... 98 5 



RUTILE. Figs, 511 to 515 inclusive. Page 428. 



Fig. 511. The primary, a right square 

 prism. 



RUTILE. 



Fig. 512. A jointed crystal formed by the 

 union of two four-sided prisms. 

 s ons 126°52' 



Figs. 513, et seq. 



M onl 135° 5' 



M ons 161 40 



/ onr 132 20 



I ons . • 153 33 



r on r 123 15 



')■ on u 151 42 



ILMENITE. Figs. 516 to 518 inclusive. Page 431. 



Fig. 516. The primary, a rhombohedron. 



P onP 85059' 



Figs. 517 and 518. 



P one about 128=' 0' 



P on6 or P' on?> 123 14 



SPHENE. Figs. 519 to 528 inclusive. Page 433. 



Fig. 519. The primary, (according to 

 Beudant), an oblique rhombic prism. 



M onM' I.3303O' 



M or M'onP 121 50 



Fig. 520. The primary, (according to 

 G. Rose.) 



M on M' 76° 2' 



M or M'onP 93 1 



