What you now have is BASE rock not live rock. Base rock does not need to be cured.
MOST IMPORANTLY you need to find out if any copper based or other medications were used in the tank that this rock comes from. If you can't be certain you probably shouldn't use the rock. At the most you could have FOWLR
tank but no inverts (shrimp, snails, crabs).
Also, where and how was this rock stored?
If you do end up using this rock you will need to buy a couple of pieces of LR
to seed your tank.