Abu Bakr ibn Abi Maryam reported that he heard the Messenger of Allah, may Allah bless him and grant him peace, say: "A time is certainly coming over mankind in which there will be nothing [left] which will be of use save a dinar and a dirham." (The Musnad of Imam Ahmad ibn Hanbal)
In the beginning the Muslims used gold and silver by weight and the dinar and dirhams that they used were made by the Persians.
The first dated coins that can be assigned to the Muslims are copies of silver dirhams of the Sassanian Yezdigird III, struck during the Khalifate of Uthman, radiy'allahu anhu. These coins differ from the original ones in that an Arabic inscription is found in the obverse margins, normally reading "in the Name of Allah". Since then the writing in Arabic of the Name of Allah and parts of Qur'an on the coins became a custom in all mintings made by Muslims.
Under what was known as the coin standard of the Khalif Umar Ibn al-Khattab, the weight of 10 dirhams was equivalent to 7 dinars (mithqals).
In the year 75 (695 CE) the Khalifah Abdalmalik ordered Al-Hajjaj to mint the first dirhams, thus he established officially the standard of Umar Ibn al-Khattab. In the next year he ordered the dirhams to be minted in all the regions of the Dar al-Islam. He ordered that the coins be stamped with the sentence: "Allah is Unique, Allah is Eternal". He ordered the removal of human figures and animals from the coins and that they be replaced with letters.
This command was then carried on throughout all the history of Islam. The dinar and the dirham were both round, and the writing was stamped in concentric circles. Typically on one side it was written the "tahlil" and the "tahmid", that is, "la ilaha ill'Allah" and "alhamdulillah"; and on the other side was written the name of the Amir and the date. Later on it became common to introduce the blessings on the Prophet, salla'llahu alayhi wa sallam, and sometimes, ayats of the Qur'an.
Gold and silver coins remained official currency until the fall of the Khalifate. Since then, dozens of different national currencies were made in each of the new postcolonial national states created from the dismemberment of Dar al-Islam.
History has demonstrated repeatedly that paper money has been a permanent instrument of default and reducing the wealth of the Muslims. In addition, Islamic Law does not permit the use of a promise of payment as a medium of exchange.
According to Islamic Law...
The Islamic Dinar is a specific weight of 22k gold (.917) equivalent to 4.25 grams.
The Islamic Dirham is a specific weight of pure silver equivalent to 3.0 grams.
Umar Ibn al-Khattab established the known standard relationship between them based on their weights: "7 dinars must be equivalent to 10 dirhams."
"The Revelation undertook to mention them and attached many judgements to them, for example zakat, marriage, and hudud, etc., therefore within the Revelation they have to have a reality and specific measure for assessment [of zakat, etc.] upon which its judgements may be based rather than on the non-shari'i [other coins].
Know that there is consensus [ijma] since the beginning of Islam and the age of the Companions and the Followers that the dirham of the shari'ah is that of which ten weigh seven mithqals [weight of the dinar] of gold. . . The weight of a mithqal of gold is seventy-two grains of barley, so that the dirham which is seven-tenths of it is fifty and two-fifths grains. All these measurements are firmly established by consensus." Ibn Khaldun, Al-Muqaddimah
How is the Islamic dinar used?
1. The Islamic Dinar can be used as saving.
2. It can be used to pay zakat and dowry as required by Islamic Law.
3. It can be used to buy and sell as it is a legitimate medium of exchange.
Gold and silver are the most stable currency the world has ever seen.
From the beginning of Islam until today, the value of the Islamic bimetallic currency has remained surprisingly stable in relation to basic consumable goods:
A chicken at the time of the Prophet, salla'llahu alaihi wa sallam, cost one dirham; today, 1,400 years later, a chicken costs approximately one dirham.
In 1,400 years inflation is zero.
Could we say the same about the dollar or any other national currency in the last 25 years?
In the long term the bimetallic currency has proved to be the most stable currency. It has survived, despite all the attempts by governments to transform it into a symbolic currency by imposing a nominal value different from its weight.
Gold cannot be inflated by printing more of it; it cannot be devalued by government decree, and unlike national currencies it is an asset which does not depend upon anybody's promise to pay.
Portability and anonymity of gold are both important, but the most significant fact is that gold is an asset that is no-one else's liability.
All forms of paper assets: bonds, shares, and even bank deposits, are promises to repay money borrowed. Their value is dependent upon the investor's belief that the promise will be fulfilled. As junk bonds and the Mexican peso have illustrated, a questionable promise soon loses value.
Gold is not like this. A piece of gold is independent of the financial system, and its worth is underwritten by 5,000 years of human experience.