Occasionally you will meet people wandering around Towns & Settlements who will offer to sell you the information on the location of a buried Treasure.
If you pay them you will get an entry in your Quest Book giving you a clue to the Treasure's location and you will also be told if you need to get a Pick-axe or Spade to dig up the Treasure Chest .( You are only told to get a Pick-axe or Spade in the Quest book if you play on the 2 lowest difficulty levels.)
As a general rule:-
Anything on shores or in jungles requires a spade. ---- Anything in a cave requires a pick-axe. ---- The two in the shipwreck and the dungeon don't require anything.
There is a possibility that the Treasure Chest will be empty when you open it ( this depends on how much Luck Skill you have).
The Island with the treasure on it will be marked on the Archipelago map with a RED Cross ( see Image)
When you arrive at the Island you may find a hostile pirate ship waiting for you & some groups of hostile pirates, that you have to fight, when you go ashore.