In order to upgrade a rare or unique item in Diablo 2: Resurrected, you must first create a specific Horadric Cube recipe using the item in question. The recipe varies depending on the item you want to upgrade, butbuy Diablo 2 resurrected Runewords always calls for a Perfect gem, which is hard to come by on Normal difficulty, with the exception of the Hellforge, where you always get one when you go there to upgrade something. It is possible for them to drop randomly from Act I on Nightmare difficulty onward, butDiablo 2 resurrected runes is highly improbable that they will do so so early in the game. As a result, you are unlikely to receive your first random Perfect gem until you have progressed quite a distance through the game on Nightmare difficulty.

When you upgrade a rare or unique item, the modifiers on the item remain unchanged, but the base weapon is improved from Normal to Exceptional or from Exceptional to Elite status. As a result, its fundamental statistics, such as damage and defense, will improve. Because percentage-based modifiers affect those fundamental stats, an upgrade can make a significant difference in terms of overall performance.

The following are the recipes for upgrading rare and one-of-a-kind items:
Items are extremely rare
From ordinary rare armor to exceptional armor
Armor Diablo 2 resurrected runes is common but rare
The thul rune
Perfect Amethyst is the ral rune.
From a normal rare weapon to an exceptional weapon
Perfect Sapphire Amn rune Ort rune Amn rune Amn rune
Armor of exceptional quality and rarity
Perfect Amethyst is the pul rune ko rune.
Exceptional and extremely rare weapon
Perfect Sapphire is a rune created by the Fal rune.
Items that are one of a kind
From Ordinary Unique Armor to Extraordinary Ordinary Unique Armor
Perfect Diamond Shael rune Tal rune Shael rune
From a standard unique weapon to an exceptional weapon
Normal one-of-a-kind weapon
The Sol rune and the Ral rune are both perfect Emeralds.
Unusual armor of exceptional quality
Perfect Diamond Lem rune Ko rune Lem rune Ko rune Perfect Diamond
Extremely effective and distinctive weapon for Elite.
Unusual and exceptional weapon
Lum rune Pul rune Emerald of Perfection