Buy OSRS Amulet of chemistry
The Amulet of chemistry is a members-only amulet in Old School RuneScape that helps you make better potions. While you wear it, you have a 5% chance to brew a 4-dose potion instead of a 3-dose potion. This gives you more doses from the same herbs and vials.
Each amulet comes with 5 charges. Every time the amulet gives you an extra dose, it uses one charge. When all charges are gone, the amulet crumbles to dust. On average, one amulet lasts for about 100 potions.
This amulet is made by casting Lvl-2 Enchant on a jade amulet, which needs level 27 Magic. It works on most potions that come in less than 4 doses, such as stamina potions, extended antifire, and divine potions. It does not work on potions that always give 4 doses, like super combat potions or super antifire.
You can also use the amulet to charge the Alchemist's amulet, adding 5 charges each time. The Amulet of chemistry is tradeable and has no combat stat bonuses. It is a smart pick for players who want to save money and get more from their Herblore training.