Coin, silver base. Diameter 24 mm. Weight 12.87 grams. Condition fair. Denomination: silver base tetradrachm. Obverse description: Head of Ptolemy I, facing right, diademed with ends hanging down, aegis around neck, border of dots. Reverse description: [inscription] Eagle on thunderbolt, border of dots. Mint date: Alexandria, year 20, reign of Ptolemy XI, Alexander I.