The Sultan did not issue absolutely new varieties of coins. The coins in circulation in his reign were already there in the time of Muhammad Tughluq. Sham-i-Siraj Afif attributes the introduction of Shashgani or six Jital piece to Firuz but Ibn Batuta also refers to such a coin.
However, it cannot be denied that Firuz introduced two coins described as Adha (half Jital) and Bikh (quarter Jital). These coins were mixed copper and silver and were intended to facilitate the transactions of the common people but there was a lot of fraud and corruption in the working of the mint.
It is stated that two informers reported that six Jital pieces were a grain short of standard purity. Khan-i-Jahan Maqbul, the minister, sent for Kajar Shah, the mint-master and directed him to find out a method by which the Sultan could be satisfied about the purity of the coin. Kajar Shah arranged that the coins should be melted before the metal was tested.
He also approached the goldsmiths whose duty was to conduct the experiment in the presence of the king and requested them to put secretly into crucible sufficient silver to bring the molten metal to the standard of purity.
They pointed out the difficulty of doing so but promised to do the needful if silver was placed within their reach. Kajar Shah got the necessary quantity of silver concealed in one of the pieces of charcoal used for heating the crucible and goldsmiths succeeded in conveying it into vessel without being observed.
When the metal was tested, it was found to be of the standard purity. Kajar Shah was carried through the city on one of the royal elephants to proclaim his honesty and the two informers were hanished.