Didn’t PING and others make beryllium clubs? My Dad had a whole set - and I have a PING Beryllium Anser II putter.
But didn’t they quit making them because they found out that somehow the beryllium was dangerous?
And Bendix used it to make rocket parts.
Beryllium is used in Defense and Aerospace applications. It is very rigid and does not flex.
Here is a good midswestern company that makes beryllium alloys and castings.
https://ibcadvancedalloys.com/