RUMBLETiGER
Adventurer
A reef is primarily built of coral, and only certain kinds that build hard casings, as opposed to more delicate, deep-water corals.
I agree, the crafting of coral would be an important step in an Island making process. I'm figuring the Druid will have spend 100+, possibly a fe hundred years in the manufacturing of his island, he'd have plenty of time to encourage coral life. Thanks for the education.
Someone needs to research a Transmute Water to Stone spell. Just stand on a boat over one spot, cast it over and over every day, and create sheets of rock out of sea water...
That would also fall under Polymorph Any Object, would it not? Alternatively, there's Ice until a more rock-like substance could be generated.