Kylight is a rare mineral found in the Arctic Circle.
The rare mineral is used in Tony Stark's artificial heart and in most of the inventions in Howard Stark's Vault, the Stark Laser Harness, and the Holographic Disguise Mask. It caused the Living Laser's sickness and Whitney's also. There is an abandoned Stark outpost in the Arctic that houses most of the ore. Iron Man in his Arctic Armor went there to get it, but Blizzard arrived and froze the last sample. Tony had one chance left, use the ore in his heart to make an antidote. Once that was done, Whitney's life was saved.