you will need quite a few black sapphire, jacinth, diamond and blue diamond. If you dont have any on you, there are merchants around the world you can buy them from. I use two merchants in Abysmal Sea (port code: abysmal): Tialechaety Orrthemech, a tinkering vendor, who sells black sapphires, and general goods vendor Tasec Dreeng. Both are close to each other in the hold of the boat.
That's from official wiki. Just went to Abysmal Sea and /target Tialechaety and I see where the NPC should be but its not there...same with the other NPC. Any other tips where to get the gems? I am running PoK looking now w/o any luck.