Switzerland
Confederation gold Matte-Proof Medallic 1000 Francs 2006 Solothurn, MS69 PCGS This actually appears to be a Gem Matte Proof, as one can tell if they look closely and see the sand blasted surfaces. Unlisted in the standard references, but reported to have mintage of just 25 pieces. Extremely rare.
Estimate: 3000-4000 USD