From Emanuele Fornasier:

This video is the beginning of a long term chemistry project involving metal crystals.

These stunning structures are the result of a chemical reaction where the metal is deposited from the solution onto the metal surface. It takes from a few hours to a couple of days to generate a crystal. This process is carried out very slowly by an electric current: layer by layer the crystal is born.

[Source: Emanuele Fornasier on Youtube]