In Numismatics, the 'head' side of a coin is called obverse and the 'tails' side is called reverse. Field is the surface of the coin where the designer and engravers place letters and figures. This is often enclosed by a circular line called the rim. Motives on Islamic coins are generally limited to inscriptions covering almost all the field and some adornment.
Historically the most commonly used metals for coinage were gold, silver, copper and alloys. The value of the metal depends on the weight of each piece and the purity of the metal.
Minting consists of placing a disk of metal between two dies with the obverse and reverse engraved on them and pressing them all together with a hard strike. This is the method used by the inventors of coins and is still used today. In the 16th and 17th centuries coins were produced using cylindrical mints that firmly pressed a sheet of metal, which was then cut into pieces.
Other methods, such as melting pieces into mouds, have been used little as they are low quality and easily falsified.