Treasure hunting

It could be interesting to add a "treasure hunt" in Minecraft. I was thinking on adding some underground "ancient structures" like a tomb, where it could be found some interesting items and new items called "light mineral" a thinner version of the mineral which can be used to craft "dagger" a faster and thinner version of the normal sword. These structures can also be found with a map obtained by trading with a new kind of villager called "Treasure Hoarder" or more simply "Explorer". This villager can only be found (With a low chance) in the pillager's outpost cage.