Astral rune

Astral Rune is a members-only item on the OSRS Grand Exchange in the runes category.

In-game examine text: "Used for Lunar spells."

It has a Grand Exchange buy limit of 25,000 every four hours, a high alchemy value of 30 gp, and item ID 9075.

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Astral Rune shows an active flip setup with a margin of +2 gp and 9,970,553 trades over the last 24 hours.

At the buy limit of 25,000 every four hours, max profit per cycle is about 50.0k gp — high margin with healthy liquidity.