Pisidium personatum is a species of freshwater bivalve from the family Sphaeriidae.
The 2.5-3.5 mm shell is a characteristic round-regular oval shape.
It has centrally placed low, rounded umbos.
The surface (periostracum) is dull or silky with very fine irregular concentric striations.
The colour is yellowish to greyish but it is invariably coated in a red-brown to dark brown deposit.