Teleportation Quest
 

Where do you find the buried tortugan treasure chest with an artifact? I've dug at almost every location I can find, but can't seem to get it.

I think it's random, it's not in the same spot for every player. Try near the Tortuga jail, or near Hendry Cutts, or behind The Faithful Bride. If you don't find it, switch servers and try those spots again.

A good spot to try is by Fabiola. There's a hill near her, and on top of that hill there's a flat area with a dig spot. I usually have good luck there.

that spot is where i found mine