Ekati Diamond Mine and Stewart Blusson who had been prospecting in the region for almost ten years, having found kimberlite indicator minerals as early as 1985. The Point Lake kimberlite was determined to be uneconomic, but its discovery precipitated one of largest staking rushes in mining history, covering most of the area between Yellowknife and the Arctic coast. There are 156 known kimberlite pipes within the Ekati block of claims, including the Point Lake pipe. Ekati officially began operations on October 14, 1998, and was operated by BHP Billiton Canada Inc., a part of the BHP Billiton Group, the world's largest diversified resources
Crystallographic defects in diamond inclusions. Gray color in some diamonds from the Argyle mine in Australia is often associated with those hydrogen defects, but again, this assignment is yet unproven. When diamonds are grown by the high-pressure high-temperature technique, nickel, cobalt or some other metals are usually added into the growth medium to facilitate catalytically the conversion of graphite into diamond. As a result, metallic inclusions are formed. Besides, isolated nickel and cobalt atoms incorporate into diamond lattice, as demonstrated through characteristic hyperfine structure in electron paramagnetic resonance, optical absorption and photoluminescence spectra, and the concentration of isolated nickel can reach 0.01%. This fact