l6 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



has resulted from a metamorphism of the lime-bearing felspars; while during the 

 process of change from basic felspar to scapolite, and from scapolite to hydrated 

 aluminium silicates, and from these to aluminium oxide, " the slowly liberated 

 oxide may assume the crystalline form, and thus give rise to corundum." Among 

 other minerals found in the/ corundiferous limestone are pyrrhotite, hematite, 

 apatite, graphite and spinel. 



In Ceylon, in the peninsula of India, and in China, there are numerous occur- 

 rences of corundum in crystalline schists; and in almost every case the mineral 

 is of the gem variety. As far as known to the writer, there are no deposits in 

 Asia now exploited for use in the arts, saving the emery of Asia Minor. 



In the United States corundum is confined almost wholly to the region of the 

 Appalachian Mountains, along a belt that extends from New Jersey to Alabama. 

 In the form of emery it is found at Chester. Massachusetts, in a chlorite belt about 

 twenty feet wide, that lies between formations of hornblende-schist and talc, and 

 traverses the mountains for about four miles. There is also a productive emery 

 mine in Westchester county, New York, which ships from 500 to 700 tons of 

 abrasive emery per annum. 



Along the Appalachian mountain chain corundum is found in felspar veins 

 and associated with chlorite in peridotite and serpentine rocks, in amphibolite, 

 dunite and gneiss, as well as in gravel-beds. The principal deposits are found in 

 association with magnesian rocks, chiefly perid'otites, which occur as small len- 

 ticular masses in gneiss. As a rule, however, the corundum is neither in the 

 peridotite nor in the gneiss, but in a narrow zone of chloritic minerals between the 

 two. The largest known areas are in the south-western counties of North Carolina, 

 where corundum was first discovered in 1870. This state has furnished nearly all 

 the corundum of commerce for the United States, but the statistics of the mines 

 and works have never been published. There has been much waste of eflfort in 

 mining for the gem varieties, encouraged by occasional discoveries, but chiefly 

 by the attractive colors in which the corundum is found. The whole process of 

 mining and milling has had to be learned by experience; and the task has been 

 made difficult not only by the character of the formations, which is not favorable 

 to sinking or drifting, but also by the closeness with which the corundum crystals 

 adhere to the matrix. •!> For abrasive use it is vei-y important that the corundum 

 should be free from particles of rock or mineral softer than itself; and for use as 

 an ore of aluminium it should be free from all impurities, to make extraction 

 practicable by present methods. 



The first discovery of corundum in Ontario was made by the late Sterry Hunt 

 fifty-one years ago, in the second year of his connection with the Geological Survey 

 of Canada. Dr. Hunt explored part of the county of Lanark in 1847. He was 

 joined in some of his excursijans by Dr. Wilson, of Perth, who at that time enjoyed 

 some local reputation as a geologist (the mineral wilsonite is named after him), 

 and who is still remembered as a man who paid considerable attention to the 

 natural history of his district. The first place visited by them was the fourth lot 

 on the eighth range of the Township of Burgess, upon which Dr. Wilson a short 

 time before had discovered a body of apatite. Near by, on the second lot on the 

 ninth range, was a deposit of copper pyrites in crystalline limestone, and this was 

 also visited. The only exploration work consisted of two or three blasts, and 

 amono- the masses of rock thrown out were some consi-sting of silvery mica, with 

 quartz, felspar or albite, and calcspar, holding a delicate emerald-green and almost 

 transparent pyroxene of rare beauty, as well as crystals of a dark honey-yellow 



(i) Mr. Alexander Rickard of New York, who is owner of a corundum property at Energy, in York County, 

 South Carolina, says, in a letter to me of recent date : " All our corundums are very difficult to clean. While 

 the gangue is soft, it is tough, and adheres to the grains of corundum when it is broken up. This reduces the 

 cutting value, and also creates trouble by fluxing when making into wheels." 



