What do I mix with yellow polymer clay to get it golden yellow?

I'm trying to make an easy egg ring out of polymer clay and I only have this bright yellow clay. It's too bright to be the color of an egg yolk, so I need to get it golden yellow. But I don't know what to mix the yellow with to get the color. I have tan, brown, orange and black clay to mix it with; those are the most reasonable colors that I think may create golden yellow. So, could anyone help me figure out what color to mix it with? Thanks!