Harvard - Smithsonian
Center for Astrophysics

Rust was found in Apollo 16 rocks
http://adsabs.harvard.edu/full/1982LPSC...12..253H

They attribute rust to "contamination" and "fugitive element localization" (wandering of chemicals)
rather than seeing rust as evidence of a fraud.
Clast - a rock fragment resulting from a breakdown of larger rocks

Ferric Iron Oxide (rust) is Iron
mixed with Water plus Oxygen.