A regular drill is very heavy and there is a good chance that trying to drill into a delicate seashell would cause the shell to break. With this hand drill light pressure is used to slowly drill a hole into the seashell.
HOW TO DRILL A HOLE IN A SEASHELL WITH A HAND DRILL.
First place the shell in the sink on top of a washcloth or something soft. Next, Either drizzle a small stream of water from the tap over the area you are drilling or if the shell is really small just dampen it.