An auction is a place where one could choose to sell the rare and extraordinary items in their possession. In fact, if the item one wanted to sell was considered valuable and quite rare by the masses, the selling price would be much higher than if it were sold in an official shop or the black market.
However, these exact words once again caused Emery to be confused. He couldn't wrap his head around Silva's idea that his tier 2 [Gaia Serum] would be considered as a rare one.
When they walked away from the black market, Silva finally gave him an explanation.
In reality, the spirit stones carried certain risks and could endanger one's cultivation if simply eaten orally. This was also the reason as to why spirit serum was created in the first place.
However, even the most effective spirit serum was proven to be effective only for rank 4 to rank 6 and would endanger the life of low-rank acolytes.