Cure live rock?

Can you put dry rock in your tank and let it sit to turn into live rock? Or do you need to add something to make it "live"? Prob a dumb question but curious...

Rock was live rock at one time but was allowed to dry before I got it..

Yes, you can. However, you should expect a cycle as the dead stuff on the rock starts to decompose. If you don't have any livestock in your system, this will not be a problem. If you do, you will want to cure it. Just place the rocks in a container of salt water with a pump, do a few water changes. In a couple of weeks you will have live rock. At this stage, he only "live" stuff on it will be bacteria. once it's been added to another system, other live things will migrate to it on there own.