After hearing Nine explanation, Kyle nodded with understanding. It seems they have actually found a treasure trove.
Also, when Kyle heard about the location of the cave, he was sure it was the same as one of two the golden cross marks present on this mountain.
Kyle started pondering, mana stones were precious as they were used for the activation of teleportation arrays and many other things.
Mana stones were a type of blue color stones that held abundant of mana within them and were only produced naturally.
That's why all the Kingdoms used them as a second currency after gold coins.
Also, selling one mana stone was enough for a poor family of 5-6 to live comfortably for a month because;
1 mana stone=100 gold coins,
1 gold coin= 100 silver coins,
1 silver coin= 100 bronze coins.
It would be a pity if Kyle left those precious stones for someone else.
-Unedited.