I would like to identify a mysteriously dense metal I have in my possession. I bought a big box of engineering bits, along with a lathe, and found what I thought were High Speed Steel tool blanks which felt very heavy. I worked out the relative density and it is an amazing 16.97. The material is non-magnetic and grinds like silver steel (unhardened tool steel); I haven't tried machining with it. The closest element is Tantalum at 16.7 but it's not that because tantalum is soft. The only marking on each piece is EDF 32851 and each piece is about 9 x 9 x 155mm. Any ideas?