from the brutal punishment, a monitor said Friday.
The Syrian Observatory for Human Rights said the jihadist group sentenced the woman to be "stoned for adultery" in the town of Raqa, the IS stronghold in northern Syria.
Militants carried out the punishment and "stoned her until they thought she had died," said the Britain-based monitor.
But just as they had stopped pelting her with stones, the woman stood up and tried to flee.
"An IS militant was about to open fire at her when an Islamist jurist intervened and stopped him saying it was God's will that she did not die," said the Observatory, without specifying when it happened.The IS jurist told the woman she can walk free but that she must "repent".
According to the Observatory, at least 15 people, nine of them women, have been executed by jihadists in Syria, including Al-Qaeda-linked militants, since July for alleged adultery and homosexuality.
The IS and the Al-Nusra Front, Al-Qaeda's Syria branch, hold large swathes of Syria and have imposed a brutal version of Islamic law in territory under their control.