Fire: Athame
The athame is likely the least known tool. The Smith family is known to have at least one athame, the Mars Dagger.
Water: Communion Cup/Chalice
The cup or chalice is the easiest of the tools to identify and understand due to its use in the Sacrament of Communion.
Air: Rod of Aaron
In a revelation to Oliver Cowdery, the Lord told him, through the seer stone, to use his "sprout" to translate. God was speaking of Oliver's divining rod.