Sigil of Specialised Strikes

High alchemy turns Sigil of Specialised Strikes 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 138 gp costs 100,138 gp. That is a loss of 88,138 gp per cast at its guide price, so it is not worth alching for profit right now.