^Lot 274 BOLIVIA, Potosí, cob 8 reales, 1651 O, with two crowned-C countermarks on cross (very rare), ex-Mast

BOLIVIA, Potosí, cob 8 reales, 1651 O, with two crowned-C countermarks on cross (very rare), ex-Mastalir (Plate). S-P35; KM-19b; Cal-1489. 20.03 grams. Round flan (thin and worn from corrosion) with bold assayer, full shield and cross despite flatness, the latter with bold 51 of date and two clear countermarks, toned in crevices. Pedigreed to the Roberto Mastalir Collection, with his tag, plated as 4CC-ds D16 on page 74 of his 2021 book The Great Transition at the Potosí Mint 1649-1652, The 1649-1652 Crowned Shield Coinage and the Countermarks of 1652, Part B (countermarks). Recovered from: Capitana, sunk in 1654 off Chanduy, Ecuador