Yep, while ruthenium is a platinum group metal, its more refractory than platinum which is itself already relatively difficult to work, the same reason premiums on platinum coins tend to be significantly more than gold/silver. Platinum itself wasn't a very easy to work with metal until starting in the 1980s groups of jewelers spent 20+ years developing best practices on how to work with it. As far as I'm aware, theres no standard for ruthenium outside of very specific niche applications ie machining mesh for catalytic converters or something of that sort. There are specialty ruthenium ingots out there, but you'd never find a mint to work it as I doubt the type of dies, strikes, etc needed to work it are commonly available knowledge.