Switzerland, Confederation, 20 Francs 1871, PCGS graded pattern, extremely rare

Switzerland. Confederation, since 1848. 20 Francs 1871 Pattern (6.45 g). Engraved by Durussel.
Obverse: Crowned head left, in circle of stars, date below // Reverse: HELVETIA. Shield of arms between sprigs, value below.

KM Pn19; Richter (Proben) 2-65; HMZ 2-1226a; Fr. 492.

GOLD. PATTERN. Of the highest rarity, especially in this quality. In PCGS holder, graded SP63