Onyx amulet

High alchemy turns Onyx amulet into 120,600 gp. Buying one at 2,728,141 gp (its guide price, as it has not traded today) and casting with a nature rune at 138 gp costs 2,728,279 gp. That is a loss of 2,607,679 gp per cast at its guide price, so it is not worth alching for profit right now.