Farz zakat is on wealth at one hand and on agriculture at another.now it has been added by our marjah sistani saheb that is business earnings. However i fail to understand why money which is todays medium of exchange and easy to hoard, is not included as wealth whereas the money in the form of dirham and dinar at the time of our prophet was accepted and was in circulation. Now time has changed all the trasactions take place in paper currency and is absolute replacement of dirham and dinar.in cities now the wealth in form of camel, cow, goats or agriculture etc.is nonexistent.do it means that rich of cities not to pay zakat. It does seem to be unacceptable. Many Shia scholar did ijtehat and proved that present day paper currency if anybody has above the nisab will be zakatable. For example seyed baqirussadr, great Shia scholar had the same view.