I’ve not use the gold but I have used the silver of this and it worked well. I have only washed it once so far but all the other things I have made with Gutermann threads have washed well.
https://www.cottonpatch.co.uk/acatal...iABEgJYAPD_BwE
This is a a UK supplier but I am sure you can find a US supplier easily. It isn’t metallic as metallic threads are really hard to hand quilt with I have found (they snag)