Blessed Gem – in Cathedral of the Deep make your way up to the rafters above the giant and head to the right side, it’s behind a Knight with a Greatsword, also in the rafters of Lothric Castle if you drop down the hole in the building after the three Gold Winged Knights.

Also dropped by Deacons of the Deep on your way to Anor Londo or in Anor Londo itself.

Deep Gem – in Cathedral of the Deep, head around the room with the giant and up the stairs, then go left up the next stairs and head up to a balcony with an Evangelist enemy the gem is on a corpse here.

Hollow Gem – from the Farron Keep Perimeter bonfire turn around and head forward until you reach a hole in the wall to your right, drop down to a ledge with this item on a corpse or drop down off the roof in the Grand Archives (after the first Gargoyle) and find it on a corpse in a corridor behind you.

Crystal Gem – kill Crystal Lizard in the building before Crystal Sage boss fight or dropped by Sorceror Hollows in Crucifixion Woods.

Raw Gem – kill Crystal Lizard on roof with Pus of Man enemy in High Wall of Lothric or can drop from the hollow enemies in this area.

Heavy Gem – speak to Hawkwood at Firelink after you kill the Crystal Sage or dropped by Crystal Lizard in ravine (on way to find Irina) in Undead Settlement.

Refined Gem – on a corpse between the two dragons in Lothric Castle or dropped by a Crystal Lizard in the Grand Archives.

Fire Gem – can be chosen as a starting gift or dropped by the Fire Demon you fight with Siegwald in the Undead Settlement.

You’ll also need the relevant gems which can be found in a few places or dropped by enemies, but here is a helpful guide:

Allows Lightning, Simple and Chaos infusion. Enter the doorway through here to find the coal on the giant blacksmiths corpse. From the bonfire, head up the stairs and hand a left. On the left side (facing the main exit) is a room full of malformed beasts, the coal is on a body in this room. In the same large room where you find multiple jailers and Karla the Witch is locked up. Profaned Coal – found in Irithyll Dungeon.Allows Crystal, Blessed and Deep infusion. From the first bonfire head left through the swamp until you come to a tower guarded by a Darkwraith, the coal is on a body inside. Hand a right here and head down to a Black Knight the coal is on a body just past him. From the Halfway Fortress bonfire go straight ahead and drop down the ledges on the right side, past some poison beasts and crucified undead and into a door at the end. Farron Coal – found in the Road of Sacrifices.To get them all you’ll need the following:

To infuse a weapon you need to take it to Blacksmith Andre in Firelink Shrine, you most have to relevant coal and the necessary gem stone.

Fire gem dark souls 3