It does not look like metal, but I never seen it personally, so I do not say more. Without any data upon PMs percentages, you will probably have hard time to sell it here. I would personally smelt it to the dore/button and get it at least analysed with good XRF machine to prove yourself. XRF on PM mode of METALLIC button is perfectly OK. Then, it begin to take some traction - as we are used to inflated stories about PGM deposits and other miracle stuff presented here on GRF weekly, take my scepticism with a grain of salt
PS: slag can many times look exactly like a metal, with the difference that it simply isn´t. But it is easily recognized, many times even by feeling the weight, or panning crushed stuff. If there are any PGMs to be found, residue (even 90+% base metals) would be far more heavier as the rest of the stuff. Thing is alloys produced can be many times very similarly brittle than the slag alone (most of the times vastly exaggerated, but point is there), so by simply smacking it with hammer, it can be hard to tell the difference if you are not familiar with it.