you could oxidise some silver wire to a deep black with liver of
sulphur. There is a product called Jax Black, available from many
vendors that is applied to a variety of wires, i believe, other than
precious (copper, brass, etc. for instance) although silver may be
acceptable- you would have to check it out (i don’t use the stuff
but have seen it at a friend’s studio) but i do know it’s more
permanent than most coated products that are on the market and
doesn’t scratch off easily if at all with normal wear. As for solid
black wire, iron binding wire (dead soft as found in hardware stores,
etc.) is the only black wire I can think of but the processing but it
would have to be work hardened and then there’s the fact it’s iron!
J. L Collier makes some fantastic jewellery in mixed metals using
iron and other ferrous metals, as do other art metalsmiths, but you
would have to get used to mixing ferrous and non ferrous in
soldering, pickling, etc. as it requires some planning. Other than a
coated aluminium “craft” wire, (but they are quite easily scratched
and marred) that i wouldn’t recommend in any case, oxidising your own
may be the best option. rer