If the liquid is denser than the coin, then the coin will eventually
come to rest floating, with part of it above the surface of the liquid.
That's exactly the situation if you drop the coin into mercury.
Density of copper . . . 8.96 gm/cm³
iron . . . 7.87
zinc . . . 7.13
silver . . 10.5
nickel . . .8.91
lead . . . 11.4
Density of mercury . . . 13.53 gm/cm³ !