A simple and low-cost roasting modification for improving nickel extraction from relatively refractory and low-grade nickel- and cobalt-bearing weathered serpentine was demonstrated on a laboratory scale using the reductive roast-ammonia leach process. Reductive roasting at 750 deg. C of weathered serpentine mixed with only 4 pounds of pyrite per ton of ore enabled extracting 83 percent of the nickel, whereas only 68 percent of the nickel was extracted when pyrite was not used. Improved nickel extraction was achieved with Philippine and Caribbean ores. Little, if any, improvement in cobalt extraction was gained using pyrite.