Seventh-level energy stone!
Every seventh-level energy stone was worth at least a thousand sixth-level energy stones!
This was based on the effects of cultivation.
The cultivation effect of a seventh-level energy stone was more than ten times that of a sixth-level energy stone.
The sixth level energy stone was enough for a heaven-stage martial warrior to cultivate.
There was no need to mention the seventh-level. This was a common cultivation resource used by most universe stage martial warriors.
Energy stones were the best cultivation resources for a formidable martial warrior. The level of the energy stones would affect one's cultivation speed and the quality of the Force one cultivated.
In summary, the higher the level of the energy stone, the rarer it was.
Light element seventh-level energy stones were even more precious. Many universe stage light element martial warriors had to pay a higher price to obtain these energy stones.
