These are ancient artifacts from the Old World that are always found in ancient debris in the vicinity of old world ruins. These are collectibles, at the same time valuable tradeable items that are part of a set. You can trade these to a special merchant in Meridian for a hefty amount of shards and random modifications per set. There are a total of 12 ancient vessels scattered in the world, 4 for each set.
Before looking for Ancient Vessels, it will be a good idea to get the special map first from the merchant near the main gate right after becoming a Seeker and before leaving to investigate the area beyond the gates.
The ancient vessel’s general vicinity will be marked in the map, not its exact location. You have to use your Focus and look for the purple container signal. When you’re near the ancient debris containing the vessel, you’ll immediately see the purple marker.
Upon reaching Meridian, you can talk to a specialty merchant named Studious Palas who is looking for Ancient Vessels. You can trade the vessels in sets of four, as listed below. Each Reward Box contains 500 shards and 5 Modification Boxes. Each modification box contains a random uncommon or rare mod.
Palas’ Reward Box I
Palas’ Reward Box II
Palas’ Reward Box III