Sigil of Finality

High alchemy turns Sigil of Finality into 18,000 gp. Buying one at 200,000 gp (its guide price, as it has not traded today) and casting with a nature rune at 137 gp costs 200,137 gp. That is a loss of 182,137 gp per cast at its guide price, so it is not worth alching for profit right now.