|Spring Leaf of Holly in tantalum.
Shire Post Mint makes and sells an extensive line of fantasy coins based on the stories and worlds of the Lord of the Rings, Star Trek, George R.R. Martin, and others. What I like about this of course is the fact that many of them are made of unusual elements including titanium, niobium, and even hafnium (click the Sample Group link below to see the others).
The card for this one says it's made of Mythril (his name for niobium) but it's actually a test strike in tantalum. It didn't come out perfect (note the flaw on one side, visible in the rotation video), so the tantalum version isn't available for ordering.
Other versions in niobium are probably still available, so you can buy this coin from Shire Post Mint. (And if not, they have many others like it: If that link doesn't work, go to their home page and follow the links to find lots of coins.)
Source: Shire Post Mint
Contributor: Shire Post Mint
Acquired: 10 June, 2006
Text Updated: 11 August, 2007
Sample Group: Coins