High Quality Content by WIKIPEDIA articles! Operation Sandstone was a series of nuclear weapon tests in 1948. It was the third series of American tests, following Crossroads and preceding Ranger. Like the Crossroads tests, the Sandstone tests were carried at the Pacific Proving Grounds, although at Enewetak Atoll rather than Bikini Atoll, but differed from Crossroads in that they were primarily conducted by the Atomic Energy Commission, with the armed forces having only a supporting role. The purpose of the Sandstone tests was also different, in that they were primarily tests of new bomb designs rather than the effects of nuclear weapons.