Occult Gems are part of the new features introduced inDiablo 4’sSeason of Witchcraft. They work hand-in-hand with Witchcraft Powers, either by improving the latter’s effects or providing completely new ones, provided players can meet their requirements.
While they aren’t totally necessary to making agoodDiablo 4build, Occult Gems can massively improve your strength as you climb through the Torment levels and beyond. Here’s a cheat sheet containing all the Occult Gems and their recipes.

All Diablo 4 Occult Gems and Recipes
Occult Gems require a ton of Gem Fragments, and in order to craft the simplest of these gems, youneed to collect Fugitive Heads. you may get the latter by defeating Fugitive Head bosses in Headhunt zones.
As for Gem Fragments, you can also farm them in decent quantities in Headhunt zones during Season 7. If you want to get large quantities of them in one go, finish an Infernal Hordes run andopen the materials chest at the end.

Elder Sigil
Agility, Corpse, Incarnate, Mastery, Weapon Mastery, and Wrath skills deal 25% increased direct damage to Hexed enemies.
Vulture Talon
While you have an Aura active, DoT effects tick 50% faster.
Recipe
Killing Wind
While you have three or more Eldritch powers equipped, gain 15% Critical Strike Chance and 25% Movement Speed.
Cornucopia
While you have three or more Growth & Decay powers equipped, generate 30% more Barrier and Fortify, and gain 30% more Thorns.
Hungering Void
While you have an Aura active, pull Nearby enemies toward you every 8 seconds.
Vile Phylactery
While you have a Summon Witch Power, fatal damage is prevented. You then gain a Barrier equal to 100% of your Max Life, and all Summon Witch Powers are disabled for 6 seconds. Occurs once every 75 seconds.
Spiral Coin
While you have three or more Psyche powers equipped, gain 30% Crowd Control Duration and 20% Lucky Hit Chance.
Dust Stone
Enemies take 2.5% more damage for each Aura and Hex affecting them.
Witching Hour
While you have three or more Eldritch powers equipped, every 1 second, the next Core skill you cast counts as an Eldritch Witch Power.
Mind Wreath
While you have three or more Psychepowers eqipped, your Defensive, Macabre, Trap Skills gain 20% Cooldown Reduction.
Voice of the Stars
While you have an Aura active, your Ultimate is treated as all Witchcraft Power tags and deals 10% more damage.
Friend of the Bog
While you have three or more Growth & Decay equipped, gain 8% more Primary Core Stats, 10% Max Life, and Unhindered.
Moonlight Ward
For each rank of your Unique Witchcraft Power, gain 3% Damage Reduction and 0.5% Maximum Resistance to All Elements.
All Occult Gems also provide 160 Armor and 8% Resistance to All Elements, both of which are necessary forsurviving Torment 1 and above. Only one copy of a gem can be equipped at a time, and they can only be slotted into accessories.