In those cases, many power gems were joined together. The result was greatly augmented or joined capabilities. Without something to bring them in line, so many power gems together would result in mutual destruction. However, putting an Emperor Stone in its center served to stabilize these erratic energies. It made them safe and effective. Even particularly powerful – and, thus, dangerous – gems were not a threat when the Emperor Stone was part of the picture. In short, it made whatever it was equipped to better – that was its purpose, stability and strength.
Judging by the size of Jun Yongye’s prize, it was good enough to power the gem lattice of a scout ship. It was worth more money than most people would see in their lifetimes.