During the time Han Solo was frozen in carbonite, Luke Skywalker constructed another lightsaber to replace the one he'd lost on Cloud City. He found plans for doing so in an old leather-bound book he found at Ben Kenobi's old hut on Tatooine, according to "Shadows of the Empire". A lightsaber consisted of power cells, electronic controls, control circuit boards, superconductors, a high-energy reflector cup, and one to three focusing jewels. The best lightsabers used natural jewels, but jewels could also be made from the proper ingredients by cooking them at very high heat and pressure. Then one cut the jewel, polished and installed it, and tuned the photoharmonics.