Adamantine are one of the GF Learning Items in Final Fantasy 8. Listed below are the effects of the Adamantine. Where you can find the Adamantine and how to obtain the Adamantine.
Adamantine - Allows the Guardian Force to learn the Vit+60% ability - The Adamantine can be dropped by the Adamantoise. It can also be refined from 10 Orihalcons. It can also be refined from the Minotaur Card
More guides can be seen at the Final Fantasy 8 Forums.The complete list of all GF learning items can be found at FF8 Guardian Force Learning Items Guide. If you have more info about Adamantine please post them below.