First of all i wold ipgrade equipment

Personally, I used the blue stones for missions and upgrades to equipment and pet, it is only convenient when they are q1 not to lose. exchange with the pink stone I preferred to sell it and take gold for upgrade to companies. If you have too many and decide to use them, first upgrade the equipment (gloves, boots ...) and then pets...

+1 for equipments, if you spend a pink stone on a pet and forget to feed in a day you lose it

If you use blue stones for pets you will loose them

Pink for tiger Blue for wolf

I have 9 blue stones and 3 pink stones