These square items seem to function as the potions cure light wounds, cure moderate wounds, cure serious wounds, and cure critical wounds. The one thing is that they seem to be able to be enchanted more than one time.
Cure Light Wounds Jade Talen 18 use item
Cure Moderate Wounds Jade Talen 9 use item
Cure Serious Wounds Jade Talen 6 use item
Cure Critical Wounds Jade Talen 3 use it