Sigil of Preservation

High alchemy turns Sigil of Preservation into 12,000 gp. Buying one at 100,000 gp (its guide price, as it has not traded today) and casting with a nature rune at 137 gp costs 100,137 gp. That is a loss of 88,137 gp per cast at its guide price, so it is not worth alching for profit right now.