The Revolution Of The Demon God: Emperor's journey
After reaching the surface, Tsarayu climbed out of the lake and wore his clothes.
After wearing clothes, Tsarayu took one of those 2 blue crystals out and observed them.
"Finally, something here that I could recognize. Now that I have these, I have the hope of going back home faster," Tsarayu said to himself, smiling.
Tsarayu had recognized these crystals as Mana crystals. These Mana crystals were the crystallization of pure Qi of nature. These crystals were highly sought after as they could be used for cultivation and could be used as the currency amongst cultivators.