Originally Posted by
Stymie52
The Onyx Pearl is the goal prize in Chapter 7, Goal 2 (Journey to the Scorched Mountain). You can get another Onyx Pearl in the market for 250 gems. It drops an Onyx Crystal every 4 hours.
I haven't heard of anyone getting the Onyx Pearl as a drop from an adventure. If they did, they should consider themselves very lucky. The Onyx Crystal only comes as a drop from the Onyx Pearl. Therein lies the problem, as you can only collect 6 in one day without using gems.
I hope this answers all your questions. Good luck!