Coin France 100 Francs Liberty - 1986 Silver Piefort 30g

In numismatics, a "piéfort" (sometimes spelled "piedfort") is a special coin or medal struck with a thickness or weight greater than that of the standard coins of the same denomination. Piéfort coins are typically thicker than regular coins and may also be heavier.

Piéforts are often produced for commemorative, collectible, or promotional purposes. They are usually crafted with particular attention to quality and finish and may exhibit sharper details and more pronounced reliefs than regular coins. Collectors often appreciate piéforts for their aesthetics and rarity.

Piéforts can be made from various metals, such as silver, gold, copper, etc., depending on the specific coin and its purpose. They are typically produced in limited editions.

It's worth noting that the term "piéfort" is primarily used in French numismatics, but similar coins may have different names in other countries. For example, in the United States, similar coins might be referred to as "double thickness" or "double struck" coins.