stone (n.)
Old English stan, used of common rocks, precious gems, concretions in the body, memorial stones, from Proto-Germanic *stainaz (cognates: Old Norse steinn, Danish steen, Old Saxon sten, Old Frisian sten, Dutch steen, Old High German stein, German Stein, Gothic stains), from PIE *stoi-no-, suffixed form of root *stai- "stone," also "to thicken, stiffen" (cognates: Sanskrit styayate "curdles, becomes hard;" Avestan stay- "heap;" Greek stear "fat, tallow," stia, stion "pebble;" Old Church Slavonic stena, Russian stiena "wall").

Sense of "testicle" is from late Old English. The British measure of weight (usually equal to 14 pounds) is from late 14c., originally a specific stone. Stone-fruit, one with a pit, is from 1520s. Stone's throw for "a short distance" is attested from 1580s. Stone Age is from 1864. To kill two birds with one stone is first attested 1650s. To leave no stone unturned is from 1540s.
stone (adj.)
"made of stone," Old English (which also had stænan "stonen"); see stone (n.). As an intensifying adjective recorded from 1935, first recorded in black slang, probably from earlier use in phrases like stone blind (late 14c., literally "blind as a stone"), stone deaf, stone-cold (1590s), etc. Stone cold sober dates from 1937.
stone (v.)
c.1200, "to pelt with stones," from stone (n.). From c.1600 as "to fit with stones;" 1630s as "to free from stones" (of fruit, etc.). Related: Stoned; stoning.