That's not a wedding ring, according to close up photos and translations of the characters. Scroll down about half-way...
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Another Obama mystery: He wore a wedding ring as a single man "WND asked Egyptian-born Islamic scholar Mark A. Gabriel, Ph.D., to examine the above close-up photos of Obama’s ring. Gabriel’s expert opinion is that the ring is inscribed with these words in Arabic:
There is no god but Allah
That phrase is the first half of the Shahada. The Shahada is the first of the Five Pillars of Islam, expressing the two fundamental beliefs that make a person a Muslim:
There is no god but Allah
Muhammad is Allah’s prophet"