Blue Crystals are the Goddess crying, which the game means literally. A statue out in the swamp sheds them once a week, and they are the reason you can put a collar on a zombie at all.
There are two ways to get hold of them and one of them is a shop, so nobody is forced to make the trip. The trip is much cheaper.
The statue sheds them every Envy day
The Goddess statue stands in the swamp and her tears collect around her once a week, on the fourth day. Breaking the deposit gives four crystals, and the fairy who sends you there says as much before you arrive.
The fairy told me I could find blue crystals here.
I shed them every [Envy]. Grieving over what has happened to this world.
At the Goddess statue in the swamp
So the crystals are on the same weekly clock as the resurrections that consume the collars they become. Envy day powers the Resurrection Room and refills the statue on the same morning, which is tidier than it first looks.
Gunter sells them, ten at a time
the Astrologer stocks ten 
Blue Crystals in his tower. They are hidden at his first tier and on the shelf from his second onward, priced at 75 apiece before the shop curve moves it.
Ten a restock against four a week from the statue makes him the faster source by a distance, which matters the moment you start collaring more than one zombie a week.
Every zombie collar is a crystal and an ingot
All three collars are made at the 
Jewelry Table and all three want exactly one Blue Crystal. What changes between them is the metal, the 
Faith and the mastery, and the crystal count never moves.
| Bronze Zombie Collar | 1 Bronze Ingot | 1 | 3 | 4 | 8 |
| Golden Zombie Collar | 1 Golden ingot | 1 | 5 | 8 | 12 |
| Steel Zombie Collar | 1 Steel Ingot | 1 | 10 | 12 | 16 |
Nothing in Graveyard Keeper 2 produces a Steel Ingot. Sixteen recipes ask for one and no craft, vendor, fight, body or fishing spot hands one over, so the steel collar is a recipe you can read and never run.
The Golden Zombie Collar is the real top of the ladder. Plan the crystal budget around bronze and gold, because the third row is decoration.
That makes the arithmetic simple. Every a zombie you intend to collar is one crystal, so a week of four tears collars four zombies and anything faster than that means a visit to the tower.
The other 230 recipes
Crystals are also an 
alchemy reagent, and a heavily used one. They appear in 230 mixes, which is more than most things on the shelf, so a stack set aside for the bench disappears faster than a stack set aside for collars.
They carry the alchemy bag group as well as the universal one, which is the game quietly agreeing that this is a reagent first and a jewelry component second. Keep the two purposes in separate piles.
Questions about Blue Crystals in Graveyard Keeper 2
Where do I get Blue Crystals?
Two places. The Goddess statue in the swamp sheds them every Envy day and the deposit gives four, and the Astrologer stocks ten in his tower from his second tier onward.
What are Blue Crystals used for?
Zombie collars, one crystal each for all three, and 230 alchemy mixes. Nothing else in the game wants one.
How often do the crystals come back at the statue?
Once a week, on Envy day, which is the fourth of the six. That is the same day the storm powers the Resurrection Room, so a trip out there fits the same morning as the resurrections.
Why can I not make the Steel Zombie Collar?
Because nothing in the game makes a Steel Ingot. Sixteen recipes ask for one and no source of any kind produces it, so the Golden Zombie Collar is the best collar you can hold.
How much does a Blue Crystal cost?
Seventy five before the shop moves it. Gunter holds ten, and buying into a full shelf is the cheapest the price ever gets.
Needed By
More Items
MaterialAcid
Building MaterialAdvanced Detail
ToolAdvanced RodAlchemyAlbedo Tear
AlchemyAlchemic Powder (Blue Rune x2)
AlchemyAlchemic Powder (Blue Rune x3)
