This is a very easy way to make quite a bit of money synthing Horn Hairpins and selling them to the Bonecraft guild in Windurst Woods.
Required: Any job over 45 (either RNG/THF or THF/RNG is recommended for Wide Scan/Tresure Hunter), 25+ Bonecraft, patience.
Head out to La Theine Plateau and begin hunting Battering Rams. After a while, Wind weather should appear. At this time, either use Wide Scan or go near the large rifts in
the ground and find an Air Elemental. Kill it to get 1-3 Wind Clusters. Use the clusters to make them into 12 crystals. Then face Southwest and use a Wind Crystal, with 1 Ram Horn as the ingredients. With a bit of luck, and maybe a skill-up, you should synthesize a Horn Hairpin. You can take these to the guild at any time it is open and sell each one for about 1.4k gil, which will add up over time.