Blood Gem System#
In the official Chinese text, Blood Gems are also called blood crystal stones (Blood Gems). They are the core system in Bloodborne that turns a weapon from merely usable into genuinely good: gems do not raise a weapon’s level, they are socketed into the slots a weapon already has, directly rewriting its damage structure and added effects. The whole system only asks you to remember three things—shape decides whether it can be socketed, the effect family decides which direction it scales, and rating plus dungeon depth decide the numerical ceiling. This page lists no concrete percentages, only criteria: once you understand the criteria, you can judge for yourself whether any dropped gem is worth keeping.
It divides the work cleanly with the Rune system: gems govern a weapon’s damage structure, runes govern the Hunter’s own passive abilities, and neither can replace the other.
Shape and Slot Matching Criteria#
A gem comes in one of five shapes, and weapon slots are divided by shape in the same way; if the shape does not match, the gem cannot be socketed, no matter how good the gem is. This is the first threshold in every judgement.
| Shape | Slot match | Main sources and traits |
|---|---|---|
| Radial | Radial slot | The most common; dropped in large numbers by ordinary enemies and dungeon mobs |
| Triangular | Triangular slot | Dropped less often than Radial; sources increase in the mid-to-late game |
| Waning | Waning slot | Relatively rare; concentrated drops from some main-story enemies |
| Circular | Circular slot | Serves only Bloodtinge weapons; ordinary weapons have no circular slot at all |
| Droplet | Fits any slot | Boss drops in the main story and in dungeons are mostly Droplet |
Work through three gates in order:
- A weapon’s slot shapes are fixed—upgrading and transforming never change them. When you pick up a weapon, first check what shape each of its three slots is, then decide which gem shape to farm.
- Droplet gems hold their value best. Droplet gems dropped by bosses are usable from the early game; socket one as a stopgap and replace it once you farm a higher-rated gem of the family you want.
- Circular gems are dead weight for non-Bloodtinge weapons. Only Bloodtinge weapons such as the Chikage and Simon’s Bowblade have circular slots; in any other loadout you can clear them out on sight.
One more thing to note: every weapon has at most three slots, but you do not have to wait until slots of the right shape are all filled before you start enhancing. A weapon’s slot shapes are usually mixed—a radial slot paired with a triangular slot, for example—so socket whatever acceptable gem shape you get first and leave the remaining slots empty while you wait. An empty slot carries no penalty; it is better than forcing in an unsuitable gem.
Effect Families and Weapon Directions (Qualitative)#
The effect family decides which direction a gem pushes a weapon. Gems of the same family are named by series; get the direction right first, and only then do the numbers mean anything.
| Effect family | Scaling direction | Weapon direction it suits |
|---|---|---|
| Tempering | Raises physical damage | The default first choice for almost all physical weapons |
| Fire / Bolt | Converts damage to fire or bolt and raises it | Matches enemy weaknesses; elemental-targeting builds |
| Arcane | Converts damage to Arcane | Weapons that already have high Arcane scaling |
| Nourishing | Small simultaneous boost to physical, fire, bolt and arcane | Split-damage weapons that already deal elemental damage |
| Adept | Raises only blunt and thrust physical damage | Hammer transformed modes, thrust-focused weapons |
| Bloodtinge | Raises blood damage | Bloodtinge weapons and gun-focused builds |
A few directional conclusions that are more useful than any number table:
- Conversion gems (fire, bolt, arcane) are a double-edged sword. They convert your damage into the matching element: on weapons with high Arcane scaling such as the Holy Moonlight Sword, Burial Blade and Blade of Mercy, or on a weapon with built-in bolt like Tonitrus, that is a real gain; socketed into a pure physical heavy weapon it throws away half of the physical rating you worked to build, which is a downgrade.
- Tempering is the most forgiving choice. When you do not know a boss’s weakness, stacking physical blindly never loses out; you can branch out later through your build.
- Pick Adept by reading the moveset. Weapons whose attacks are mostly slashing gain nothing from it—check the attack types of the transformed mode before choosing it.
- Poison, rapid poison, bonus damage against beasts, bonus damage against kin and continuous recovery are added effects: as a family on their own they are weak, and most of the time they show up as a gem’s secondary line, so when picking a gem look at which primary effect it is attached to.
- Nourishing is a compromise for split-damage weapons, not a universal answer. Its ceiling in all four areas is lower than the corresponding specialist gems; it is only worth using on all-round weapons that already deal elemental damage and cannot be bothered to swap gems constantly.
- Rapid poison among the added effects feeds on attack frequency. It only makes sense on fast-swinging weapons; expecting a heavy weapon to poison a boss with it is a mistaken expectation.
Farming Direction: Output Criteria of the Chalice Dungeons#
Low-rated gems accumulate naturally along the main route and are enough to finish the game. Truly high-rated gems come almost entirely from the Chalice Dungeons, and farming direction follows three criteria:
- Depth determines the rating ceiling. Dungeon depth runs from one to five; the deeper the rite, the higher the rating of the gems it drops, so endgame gem farming means heading into Depth 5 dungeons.
- The dungeon series determines the output element:
| Dungeon series | Output direction | Representative source |
|---|---|---|
| Pthumeru series | Mainly physical | The Merciless Watchers boss layer is a famous farming spot for physical gems |
| Loran series | Fire and bolt | Watchdog of the Old Lords yields fire, Loran Darkbeast yields bolt |
| Isz series | Arcane | Dropped by Ebrietas, Daughter of the Cosmos and others; the main destination for endgame Arcane gems |
- Rite offerings determine effect-line quality. When creating a map with a Root Chalice you can stack rites such as Foetid and Rotted: enemies get stronger and layouts more random, but the effect-line pool is better; in dungeons with the Cursed rite the Hunter is also weakened, in exchange for cursed gem output.
In terms of pacing, split gem farming into two phases: during the main story only pick up what comes to hand, focusing on collecting the Droplet gems bosses drop—good enough is fine; once you enter the deeper dungeons, farm the matching series for your build. Generating Depth 4 and 5 dungeons is not cheap, and if you pick the wrong direction and have to redo it, what you lose is rite materials and Blood Echoes.
Two points in the main story are worth remembering as well: boss drops are mostly Droplet, so the gems with the best early-game versatility basically come from that route; the Winter Lanterns in the later part of the main story drop Waning arcane gems in concentration, a farming spot Arcane builds can work before ever stepping into a dungeon.
Effect Line Structure and Cursed Criteria#
A gem can have at most three effect lines: primary effect, secondary effect, curse. Within the same series, the higher the rating, the stronger the primary effect and the fuller the secondary effect; cursed versions trade a negative line for a higher primary effect.
| Effect line | Content | How to read it |
|---|---|---|
| Primary effect | A percentage or flat bonus to an attribute | Decides what the gem is for; read this line before anything else |
| Secondary effect | Beast damage up, kin damage up, charged attack up, continuous recovery and so on | Decides which playstyle the gem fits; a good secondary line adds value to the gem |
| Curse | A negative cost, such as lowering the HP or stamina ceiling or raising stamina consumption | Trades a negative for a stronger primary effect; whether it is worth it depends on the playstyle |
Criteria for judging cursed gems:
- Pure damage builds built to burst bosses down can take the curse bonus. When a fight is compressed into a few dozen seconds, ceiling-type costs barely surface.
- Builds that spend long stretches exploring or fighting inside dungeons should be careful with curses that cut the HP ceiling—losing survival margin hurts more than a few extra points of attack.
- Judge the combination, not the primary effect alone. A gem with a slightly lower primary effect but a secondary effect that fits your playstyle is usually worth more in practice than a plain gem with a slightly higher primary effect.
When comparing two gems of the same series, fix an order: compare rating first (within the same series a higher rating means a stronger primary effect), then whether the secondary effect fits your playstyle, and finally whether the curse crosses your bottom line. Letting flashy secondary-effect wording catch your eye first makes it easy to hoard a pile of gems you will never use.
Slot allocation matters too: the three slots do not have to hold the same family. A common approach is to give the main slot a gem of your primary effect family and leave the other slots to recovery-type or targeting-type secondary lines, so one weapon has both damage output and sustain. This too is only a direction; how exactly you split the slots depends on whether this weapon plays the main attacker or the finisher in your build.
Removing and Reallocating#
Once socketed, a gem can be removed at any time with no loss and is kept intact, so there is no need to agonise early on over putting in the wrong one—use it, then swap when you farm something better. Duplicate low-rated gems have no value; clear them out in time. Give high-rated Droplet gems to your main weapon first, since they work in any weapon.
Finally, two points that are easy to misjudge. First, gem bonuses are unrelated to weapon level: even at +10 you do not need to change to higher-level slots, and slot shapes never change from start to finish. Second, a gem’s effect lines are fixed the moment it drops; there is no way to reroll or merge gems anywhere in the game, so farming is a one-shot deal—do not hesitate when the effect lines fit and the rating is high. Entering the next cycle, all gems carry over; this progress is never wiped.
To sum it up in one line: the shape passes, the direction is right, the effect lines fit—clear those three gates, then talk about rating. That is where the freedom of the Blood Gem system lies: the same Saw Cleaver can grow into a completely different weapon as a physical, fire or Arcane build, and all of it depends only on what you put into the slots.