Re: Coming into Its Own - Gamer Escape's Final Fantasy XIV (FFXIV, FF14) wiki

You will need to trade Christina several items to obtain the items you need to give Gerolt.
>> 10 Unidentifiable Bone & 4 Adamantite Francesca (trade for enchanted rubber)
>> 10 Unidentifiable Shell & 4 Titanium Alloy Mirror (trade for Fast-drying Carboncoat)
>> 10 Unidentifiable Ore & 4 Dispelling Arrow (Divine Water)
>> 10 Unidentifiable Seeds & 4 Kingcake (Fast-acting Allagan Catalyst)
All of these items can be bought with Poetics and Lore in MorDhona and Illdyshire.