Hi Jose -- I believe your coin is a late bull-and-horseman Jital from the central or southern area of what is now Afghanistan, probably minted in the late 13th century.
These were struck in silver as early as 750 AD with a strong design of a a humped bull lying on the ground, facing left on one side, and a horseman with a spear riding towards the right on the other side.
These coins were liked by the populace, and trade soon carried them far from their place of origin. The design was also adopted by many of the states receiving them in commerce. Their issue began in what is now eastern Afghanistan, first minted by the Shahi kings of Kabul and Gandahara, eventually spreading all the way to India.
The nicer silver versions are official issues from larger city states or sultanates, while the low-quality billon and copper issues with the extremely crude design elements were likely minted in times of crisis, or by smaller princely states or local town mints. Some could even be contemporary clandestine counterfeit issues of medieval India!
Throughout time, the design became more crude and less recognizable (see the secondary pictures). Due to inflation, the coins also dropped in value. They were initially minted in highly pure silver, but later in billon, with silver contents dropping from about 25% and eventually to a point where the coins were almost, or completely copper. Earlier issues have larger flans that allow most of the design to fit on them; later issues are on smaller, thicker flans, often cutting off much of the design.
Some of the larger copper versions have a barely recognizable humped bull, which has degenerated to be not much more than a design element stylizing the placement of the squiggles, which barely resemble any animal.
Check out these threads on worldofcoins.eu and coincommunity.com.
Our main picture comes from coincommunity, and CoinQuest thanks member amitvyas03 for use of his or her coin photo. It is a beautiful specimen.
Typical catalog values for these coins:
COPPER or LOW-QUALITY BILLON:
worn: $6 US dollars approximate catalog value
average circulated: $10
well preserved: $35
SILVER or HIGH-QUALITY BILLON:
average circulated: $18
well preserved: $45
Billon is a mixture of silver and copper. Billon of a low quality will have a brown or dark coppery look. Billon of high quality will have a silvery look with traces of red-brown.
You basically never see fully uncirculated specimens. They would sell for hundreds of dollars.