The Sapphire Scarab is treasure that can be obtained in the episode Rob Like an Egyptian in Sly Cooper: Thieves in Time. It is worth 234 coins and the time required to reach the safehouse is forty seconds.
"This priceless Egyptian relic was said to have been crafted by the Egyptian god Sobek. It is also said to make safehouses incredibly awesome when they are put on display. Thankfully, it won't roll up mounds of poo."
It is located in the right side of the pyramid. Only Sly's Mascot Costume can let him reach this treasure.