I did a little research just in case. Here are some non-magnetic metals. Stuff Lucy is useless against:
Aluminum
Lead
Copper
Brass
Zinc
Magnesium
Pot metal
Chromium (used in Stainless Steel)
Pewter
Titanium
Mercury
Gold 
Silver
Platinum
- See more at: http://www.scrapmetaljunkie.com/230/the-magnet-test-2#sthash.t6SHPr2A.dpuf