XV. An Account of the Swedish Corundum from Gellivara^ i>t 



Lapland. 



By C. T. SWEDENSTIERNA, of Stockholm, 

 / foreign member of the geological society. 



[Read January, 21st, 1814.] 



JLN the spring of 1803, when examining a series of iron ores from 

 Lapland which I had brought with me to Paris, I was greatly sur- 

 prized to find that the porphyry mortar employed in reducing one 

 of them to fine powder was scratched and lost its polish. Mr. 

 Tennant having nearly at the same time published his discovery on 

 the identity of emery with the sapphire, I was at first induced to be- 

 lieve that the said ore was merely a kind of emery. Upon a fur- 

 ther examination however, I found that this ore was as soft as any 

 other from the same place, and was chiefly composed of black and 

 red oxide of iron. These could be separated by the magnet without 

 leaving any earthy residue, which would not have been the case with 

 emery, in which the cutting substance is finely divided and inti- 

 mately connected with the oxide. I afterwards broke several spe- 

 cimens of the ore, and perceived in some of them very hard crystals 

 the largest of which were of the size of small peas, and exhibited 

 regular faces of an oblique octohedron. I at last succeeded in ex- 

 tracting about half a dozen of them of a perfectly determined form, 

 I then no longer doubted of these crystals being a variety of corun- 

 dum, which also was ascertained by my teacher in mineralogy, M. 

 Haiiy, to whom I presented the purest and most perfect specimens 



