11:7

He is the One Who created the heavens and the earth in six days – at the time when His Throne was rested on the water – so that He may test to find out which of you is the best in deeds. Now if you tell them:” You shall indeed be raised up after death,” the unbelievers would certainly say: “This is nothing but sheer magic!”
Meaning:-
Six days (time periods): The word day is not always used in the Quran to mean a 24-hour period. According to 22:47, a heavenly Day is 1000 years of our time. The Day of Judgment will be 50 000 years of our time (see 70:4). Hence, the six Days of creation refer to six eons (Eon means: a unit of time equal to a billion years. of time, known only by Allah.)
Sheer: clear; completely