I don't have a clear idea what you aspire to make as a necklace.

I think the advice from Stefany and Floor are good ideas.

You might want to consider the Softflex line that is 24 K gold (if you are not planning to cover the line with beads).

It is very strong and quite pretty! I have even knotted it to hold a pendant that went onto a gold neck-ring.

You can find it here: https://www.amazon.com/Soft-Flex-Extreme-Beading-Wire/dp/B005S4BZMU

Have fun! Jamey