Identifying a chunk of metal - Palladium?

All, I need some help identifying a chunk of metal a customer is sure
is palladium he says he found it in the mountains and wants me to
test it.It has a galena like appearance or more like chrome and is
hard and brittle.I tried to saw it with my jewelers saw and it does
not cut.Anyone know what type of test or acid I would use to
determine the identity of this material? Thanks J Morley Coyote Ridge Studio