Islamic State announces its own currency The silver coin had three different denominations: one symbolised with a spear and shield, another with a white minaret of Damascus and a third with the al-Aqsa mosque - one of the holiest sites in Islam. For the copper currency, one coin has a crescent while another more valuable coin has a palm tree. While the highest value gold coin will be worth about $694, its lowest-denomination copper coin will be just seven cents. "The purchasing power of the money they're emitting will be wholly dependent on what the purchasing power of gold, silver and copper are," Steven H. Hanke, professor of applied economics at Johns Hopkins University, told the FT. The important thing is: where are they going to get the gold and copper? Isis will have to confiscate more property through theft and the spoils of war. Isil is striving to establish a completely self-sufficient state, and oil production will be part of achieving that. It in unclear how the group will be able to resource enough of the precious metals to ensure widespread distribution of the coins. However, paying from it will not be a problem. Isil is thought to make as much as £2 million a day from the oil refineries under its control in Syria and Iraq, as well as receiving funding from supporters in the Gulf. They are thought to earn up to £5 million a month through extortion of local businesses as well as millions from selling off looted artefacts. In the past year they are estimated to have made £40 million from taking hostages, with each foreign hostage thought to be worth £3 million.