From -1 to -3 you will need 2 Super Tortoise Gem`s
From -3 to -5 you will need 3 Super Tortoise Gem`s
You cannot upgrade a non-blessed item!
Blessed items can be found in every city, dropped by the mobs or when you reborn, by choosing Blessed Reborn (random item).
Blessed Reborn:
- Reborning at level 110 (waters) - can bless boots and any weapon
- Reborning at 120 to 130 (all classes) - can bless any item