Some models have one blade, some are double-bladed. The blades, counting the curve, tend to be about 5 to 6 inches (12 1/2 to 15 cm) long. Most have very, very sharp blades so that the rocking motion is all that’s needed, with very gentle downward pressure, to cut.
Some models have one complete handle, some have a two-part handle, which is a wooden knob at the top of each end, to encourage your arms to “get” the rocking motion. In both cases, the handle will be above the blade.
Some come with special cutting boards that have a concave (bowl-shaped) indent in them, to help keep everything you are chopping in one place and to fit better the rolling motion that the blades make.
Mezzaluna are used for mincing, particularly herbs and nuts. It is good for those not trained on, or comfortable with, a chef’s knife.
If herbs are too wet, they’ll just stick.
Food can get caught between the blades in the double-bladed model. However much you’re tempted to just quickly run your finger through the two blades to clean it out, use a knife instead.
Very hard things won’t benefit from the rolling motion this blade is designed for.
“Mezzaluna” is Italian for “half-moon.”