This is what you call black
"I heard that this thing is very valuable in the sect's sage realm, but here, not many people are interested in it. That person is currently using black jade crystals to exchange for gold notes. If you want it, I can help you." Gao Wentian continued.
Only then did Ling Chuxi know that Gao Wentian had come this time to give her a gift. The GAO clan's Chamber of Commerce had a long history, so Gao Wentian must have already known the use of the black jade crystal. He had no use for it himself, so he had left this benefit to Ling Chuxi.
"Yes, of course I want it. I'll have to trouble you with this. I'll trade however much you have, and I'll pay you back with gold notes." Ling Chuxi said.