The Ruby Crystal is a Treasure found in Clan of the Cave Raccoon of Sly Cooper: Thieves in Time. It is worth 136 coins.
To get some general information (properties, detection, etc), please visit the crystals page.
Needing more energy to make the trip back to Cybertron and conquer it in the name of the Decepticons, Megatron ordered his troops to head to Burma and dig up ruby crystals. The amounts they found were such that Megatron believed they could power their entire home planet with them. Of course, the Autobots couldn't let this happen and blew the mines up. The Decepticons still managed to get away with some concentrated energon cubes filled with ruby crystal energy.
A crystal from a vermillion bird stone. After solid solution strengthening, it can be used for making equipment.