|High purity button.
This very high purity button was produced by Kaistar R&D (see Source link below if you want one) in their vacuum electron beam furnace, which Oliver Sacks and I visited in the summer of 2004. I wrote a story about the visit, which includes photographs of the incredible furnace used to produce this button and the many others they offer on eBay and direct to the element collecting hobby. I think it's safe to say that you will not find more perfect samples of transition metals anywhere.
This sort of button is hard to appreciate in a photograph: It's the great smoothness and density that make them so satisfying to hold.
Source: Kaistar R&D
Contributor: Kaistar R&D
Acquired: 6 August, 2004