Board Thread:Naruto Discussions/@comment-25192437-20150307225810/@comment-25283946-20150310162917

Probably the will of Karura made sure to take the power of Shukaku to defend her son. Iron Sand and Gold Dust are the weapon used by the Third Kazekage and Rasa, in combination with them special ability to convert chakra into magnetic forces. They imitate the sand techniques of Shukaku's jinchūriki. So the ability to control the sand is a skill That comes from Shukaku and That may use his jinchūriki. This is said in the manga when speaking for the first time of the third Kazekage's ability, and chapters later, of the fourth Kazekage's ability.