It was a treasure that was sealed within a series of large Hebitian tombs which were unearthed on Cardassia Prime two hundred years ago. They contained a variety of jewels which included glor'ya which was particularly valuable as it had the same properties of dilithium but vastly more superior. A 22nd century Cardassian known as Dujonian later managed to steal all the Hebitian glor'ya encrusted artifacts and hide them somewhere off world.
Cardassian Union scientists saw unlimited potential in them in regards to propulsion capabilities along with weapon designs. It was believed that any Cardassian who discovered the Hoard had the prize to end all prizes with its recovery eclipsing any previous accomplishment along with a great deal of prestige for the individual in question. In 2371, a number of individuals from Cardassians to mercenaries to the Romulans sought to find Dujonian's Hoard in order to make use of the glor'ya jewels. (TNG novel: Dujonian's Hoard)