i got all my magnets and white silvery ore from fishing. then you can compound the white silvery ore with another higher rank item to get white silvery.

you can collect white silvery in the mayan cave but you need one of the npcs (forgot the name again) at level 70 to get in.

another option is to buy the silvery ring in korea for 460g and compound that with a higher rank item like shown here http://wlodb.com/items/189