[Probably for the best they don't ask how the heck that hybridization is supposed to work, because Peridot doesn't know. She does have some gross theories though! Gross theories that she would gladly share over the network without much consideration for Steven's privacy or feelings.]

Infinitely, provided our gemstones stay unharmed and we don't get shattered or corrupted. That's why age isn't really a thing for us, it's more about what point at which you started existing, and what events you were or were not alive for.