272 Warren— llmenite Rocks near St. Uroain, Quebec / 



epidote, specific gravity 3*54. Less pure grains continued to sink 

 down to a specific gravity of 3*43. The true specific gravity 

 probably lies somewhat above 3*5. 



The material was further purified by fusing its fine powder 

 with sodium carbonate, which has only a slight action on the 

 sapphirine but decomposes the other minerals, including the 

 rutile and the alteration products of the sapphirine. Some- 

 thing over a gram of material was obtained in this manner, 

 which, examined under the microscope, was found to be 

 entirely free from impurities, and upon this a chemical anal- 

 ysis yielded the results given below in column 1. In the other 

 columns are given other analyses of sapphirine. 



I II III IV v VI VII 



Si0 2 13-44 14-56 14*51 14*86 14-76 12'95 12-83 



A1 2 62-98 60-49 63*11 63*25 63'23 64*44 65'59 



Fe 2 3 .--- Mn 2 3 *53 .__. .:.. *93 



CaO *38 - 



FeO 9-08 7*65 3*92 1*99 1*65 1*66 -65 



MgO 15*28 17*13 16*85 19*28 19*75 19*83 19*78 



Ign -56 *49 *34 *31 



Total 100-78 100*39 9979 99*38 99*39 99*22 99*79 



Sp.grs 3*5 3*542 3*473 3*46 3*486 



I — Mineral from St. Urbain, Quebec : Warren. 

 II — " " India : Walker and Collins, Records, Geol. 



Surv. of India, vol. xxxvi, Part I, 1907. 

 Ill — " li Fiskernas, Greenland : Stromeyer, Unters., 



Misch. Mineralk., 1871, 391. 

 IV" — " " Fiskernas, Greenland : Damour, Bull. Soc. 



Geol., vi, 315, 1849. 

 V — " " Fiskernas, Greenland : Schluttig, Inaug. Diss., 



Leipzig, xxii, 1884, and Zs. Kr., xiii, 74. 

 VI — " " Fiskernas, Greenland : Lorenzen, Medd. 



Gronl., vii, 184. 

 VII — " " Fiskernas, Greenland : Ussing, Zs. Kr., 15, 



p. 600. 



Below are given the molecular ratios derived from the above 

 analyses : FeO has been combined with MgO and listed as RO, 

 Fe 2 3 and Mn 2 3 as R 2 O s . 



I II III IV v VI VII 



Si0 o 0*224 0*242 0*242 0*247 0'246 ! 216 0*214 = 



R 2 3 *617 *593 *621 *620 *620 *631 *643 = 



RO -508 *534 *475 *508 *516 *517 -502 = 



Si0 2 2-00 2*00 2-00 2'00 2*00 2.00 2-00 



R 2 3 5*51 4*90 5*13 5*02 5*03 5*84 6*05 



RO 4*53 4-41 3-92 4*11 4*19 4*79 4*69 



