Can You Solve this Ice Diamond Riddle? ft. Vsauce’s Michael Stevens

Pure ice on it's own will not change the level of pure water because it's displacing an equal mass in volume of water, therefore even when melted the ice's mass would fill the same volume in water. One might assume the same goes for the ice w/diamond... BUT the ice is also displacing the mass of the diamond in the water, which means it displaces the the diamonds mass in volume of water, which has more volume than the diamond, so the water level would drop.

Considering another scenario where the ice cube does not have enough volume to float the mass of the diamond, and the ice cube sinks to the bottom, now all we have to consider is volume. Even with sunken ice the water level would still drop because volume=mass/density, and the density of the water would increase as it melted, which would decrease the volume.

So regardless of the ratio of diamond to ice, the water level would drop, right?