Only those who do their research know that diamond prices are negotiable at most stores. Barring Tiffany’s and online retailers there is no reason why you can’t negotiate a lower price for your diamond than the sticker price. … These are the diamond’s cut (shape), karat (size), clarity (transparency) and color.
Can you buy diamonds from villagers?
In Java Edition, journeyman-level armorer villagers have a 40% chance of offering to buy one diamond for one emerald. Expert-level toolsmith villagers have 2⁄3 chance of offering to buy one diamond for one emerald. Expert-level weaponsmith villagers always offer to buy one diamond for one emerald.