That canister was filled with an old Sram chain (totally disassembled) and filled with 1095 steel powder.
Once heated and compressed enough, the chain and powder weld together, forming a solid billet of steel.
The etch is basically soaking the metal in a ferric chloride solution. Depending on the specific elements of the steel itself, it'll etch differently. So, a steel high in carbon etches darker, but a high nickel steel won't etch much at all, and stay silver. the chainlinks you can see in the billet above are the ones that settled against the side of the canister when I was packing it in
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
It also shows that they are a nice high carbon steel (carbon makes steel strong). It's not a just a pattern, it's the actual chain.
The flipside of this is that *if* I make a blade from it (or the scouring pad billet), the edge will have dissimilar metals along its length (and somewhat unknown metals at that) so a blade will need an extra step to make it usable. Dissimilar metals aren't really a problem until I start to heat treat things. 15n20, 1095, 52100, 5160, are all steels that compliment each other, but if (and it's unlikely) the chain was made from something like D2 (an air hardening steel) the mix along the cutting edge would be a disaster.
ZZZZZZZZZZzzzzzzzzzzzzzzzzzz...