Rafforty:
It's dangerous outside, so please be careful! I'm telling you, most of the creatures living in the Frozen Labyrinth have a Silver Ice Crystal in their bodies. Bring me these crystals and you'll be well-rewarded. Black Ice Crystals are quite rare, but if you find one and bring it back to me, you'll be rewarded even more!
Oh, by the way... If you ever get any Silver Hemocytes, don't throw them away.
"How do I get Black Ice Crystals?"
"Where do I use Silver Hemocytes?"