Two of the most important aspects of a coin to consider are its diameter and whether or not the edge of the coin is milled or reeded. Using coins with the optimal attributes will help aid in sleight-of-hand moves and increase the visuals or apparent impossiblity of the magic.

In my opinion you should practice and perform using the largest coin that you can use comfortably without compromising your magic. The most common size coins used in coin magic are US Half Dollars which are 1.2" in diameter and US Silver Dollars which are 1.5" in diameter. In some rare cases a US Quarter Dollar can be used which is just under 1 inch in size but it may be hard to see. These three sizes are very easy to find even in non US currency so it's a good place to start.

Although any size coin can be used the optimal coin for your hand will be large enough to cover your two middle fingers but not large enough to hang over the sides. See the images below for an example.

The reason you want to use the largest coin possible is to aid in the visibility of your magic. As you can see below if I were to do magic with a very small coin like a US Dime it would be easy to imagine the coin could hide in the flesh of my hand.

With the US Half Dollar or US Silver Dollar you can see the coin very clearly and when it disappears or reappears it is very hard to understand where this giant coin has gone adding to the mystery.

The outer edge of the coin can impact your ability to grip the coin. As your hands sweat a smooth edge may become slippery making some sleight-of-hand moves more difficult. A reeded or milled edge contains a series of grooves or cuts spaced evenly around the coin which helps create a better grip aiding in the execution of these moves.

Please Note: While a milled/reeded edge is not a necessity the advantage they offer should be taken into consideration when choosing a coin. Therefore the optimal coin will fit across the two middle fingers and contain a reeded edge for better grip. In the next section Metal Type: Clad vs Silver we will look at the different metals coins are composed of as well as the differences and advantages they may offer.