This coin is in Extremely Fine condition, I would grade it EF40.
On the obverse, it shows an unusual oval shaped coat of arms. The background is divided into two fields, with horizontal lines on top and blank on bottom. In the foreground, two hands are shaking, with a pole topped by a liberty cap in the background. The rim of the coat of arms is a wreath, and its topped with a rising sun with sunbursts. The legend reads “Repubica Argentina * Un Peso *”.
On the reverse is a large cathedral like building (it looks like the Cabildo de Buenos Aires) with the legend “25 de Mayo : 1810-1960”.
Identification code: Argentina KM-33
Mint Mark: n/a
Country of origin: Argentina?
Composition: Nickel Clad Steel
Size: 24 mm
Other details: This was a circulating commemorative – it marks the 150th anniversary of the eviction of the Spanish viceroy from Buenos Aires. This was the first step towards independence in Argentina and it was originally undertaken as an act of loyalty to the Spanish King (who had been supplanted by a French puppet when Napoleon conquered Spain). Fascinating stuff.
The date on the coin (May 25th) is the culmination of a celebration known as May Week in Argentina.
Estimated Value: $0.75-1.50 in EF