'Yellow cake', an item of smuggling across borders is

1. The question asks to identify 'Yellow cake', which is known as an item sometimes involved in smuggling across borders. 2. 'Yellow cake' is the common name for a concentrated uranium powder, which is an intermediate product in the milling of uranium ore. 3. It typically consists of impure uranium oxide (predominantly U3O8) and gets its name from its yellowish colour. 4. Yellowcake is processed further to produce fuel for nuclear reactors or material for nuclear weapons. Due to its strategic importance in the nuclear fuel cycle and potential use in weapons, it is subject to strict controls and can be a target for illicit trafficking or smuggling. 5. It is not related to heroin, cocaine, or unrefined gold.