Buy OSRS Pillar coral
Pillar coral is a Farming item in Old School RuneScape. Players grow it by planting a pillar frag in a coral nursery. The nurseries sit underwater, just off the eastern coast of The Great Conch. You need level 52 Farming to plant it.
The main use for pillar coral is potion making. Add one pillar coral to a vial of water to make a pillar potion (unf). This needs level 62 in the relevant skill. Then add a secondary ingredient to make a super fishing potion or a super hunter potion. Five pillar coral can also be paid to protect umbral coral while it grows.
Pillar coral takes 160 minutes to grow, in four stages of 40 minutes each. A nearby gardener will watch it for a payment of 5 elkhorn coral. Planting gives 52 Farming XP, and each harvest gives 60 XP. The minimum yield is 4, and it goes up with your Farming level. At level 99 there is a decent chance of getting over 16.
Pillar coral is tradeable and noteable. It is not stackable and cannot be equipped. It weighs 0.028 kg.