Buy RS3 Ascended essence
Ascended essence is a RuneScape 3 item used to make a masterwork bow. It is made by breaking down ascension crossbows at a dragonkin anvil at the dragon forge. This needs level 99 Smithing. You can use main-hand or off-hand crossbows, as long as they are undyed. New, partly degraded, and augmented crossbows all work.
You need two units of ascended essence to make one masterwork bow. A fully repaired crossbow gives two units of essence. A crossbow below 50% charge gives only one unit, so repairing it first avoids losing half the essence. Be careful with augmented crossbows. Breaking one down destroys it and does not return the augmentor, gizmos, or any Invention experience.
Ascended essence also has another use. With level 90 Smithing, you can combine two units of essence with one sapphire to make an unimbued ascended sapphire.
The item is tradeable and noteable, and it weighs 0.453 kg. It cannot be alchemised or disassembled. Its examine text reads: "Essence extracted from ascension weapons." This makes it a key item for any player working toward a masterwork bow in RS3.