Go to El Nath - Chief Residence and speak to Robeira. After talking to Robeira, head back to Victoria Island and talk to "Grendel the Really Old" which is located in Ellinia. Next, find the Door of Dimension located at Forest of Evil II and it'll bring you to "The Path of the Glittering Crystal". Walk until the end of the path and enter the portal to defeat the wiseman's dark side to obtain the Black Charm.

Return to "Grendel the Really Old" and exchange the Black Charm for a Necklace of Strength. Return to El Nath after that and give the item to Robeira. Head on to the Holy Ground at the Snowfield. 1 Dark Crystal is requirred to answer 5 questions to obtain the Necklace of Wisdom. Again, head back to Robeira in El Nath and give her the Necklace of Wisdom.