Earth Release: Earth Quartz Technique

The user alters the atomic structure of an earthen material, converting it to glass. Doing so negates the effects of Lightning Release, which earth is ordinarily weak to. Originally conceived as a theoretical possibility by a scientist, the technique was long considered to be impossible for actual use in the field: first there was the issue of being able convert earth to glass at all, which would require years of training just to achieve the necessary purity; then there was the issue of anticipating where a lightning-based attack would strike and then accurately converting that location in time; then the glass would subsequently need to be changed back into earth, as glass is otherwise a weak material. Despite all this, Kakashi Hatake is able to do so, converting sections of his Earth-Style Wall that are about to be struck by lightning. He notes that the ability is ineffective against high concentrations of lightning, such as Chidori, because the heat that's generated would melt the glass.

Sasuke Uchiha used this technique to create a glass Kunai from a piece of rock.