This chunk of rock from the mountains on the Hai homeworld is apparently nothing more than a good luck charm, but the Hai have decorated their ships with them since the height of their empire. More superstitious Hai claim that the stones somehow reduce the nausea induced by hyperspace jumps by making travel between star systems easier.
The Hai have forgotten the true use of these stones, but adventurous captains will find that ships decorated with them are able to transit through the Unstable Wormholes leading into and throughout the Ember Wastes. This is the only way to encounter the Remnant faction without first obtaining a jump drive.

This precious artifact attunes a ship's quantum oscillations in a way that allows it to travel through certain otherwise impassible wormholes in the Ember Waste. The stones are rare and valuable, because they can only be mined from one location in the Waste.
Key Stones (note separation of the words) may also be obtained Remnant space, mined on Viminal and sold on all three of their planets, and are installed by default on their ships. While visually and functionally the same, they are distinct outfits; Hai Keystones will only sell for 12000 credits, even in Remnant space.