Radial
Right-hand weapons.
Blood Gems are slotted into weapons at the Workshop. Sockets unlock at +1, +3 and +6. Gem shape (radial, triangular, waning, circular, droplet) decides which weapon it fits; droplet fits any socket. Installation is not permanent: swap freely. A gem can carry up to three effects, and Cursed gems add one random drawback.
Shapes
Triangular
Right-hand weapons.
Waning
Right-hand weapons.
Circular
Left-hand weapons (exception: Lost Chikage).
Droplet
Any socket.
Effects
Tempering
Raises physical damage by percentage.
Adept
Raises blunt or thrust damage by percentage.
Fire
Fire damage.
Bolt
Bolt damage.
Arcane
Arcane damage.
Bloodtinge
Blood damage; rare, dropped by Bloodsucking Beasts and Labyrinth Ritekeepers.
Nourishing
Raises all damage.
Beasthunter
More damage vs beasts.
Kinhunter
More damage vs the Kin.
Striking
Stronger charge attacks.
Radiant
Reduces stamina cost.
Lethal
Boosts rally healing.
Fool
More physical damage at full HP.
Poorman
More physical damage near death.
Pulsing
Slowly regenerates HP.
Dense
Raises weapon durability.
Murky
Adds slow poison.
Dirty
Adds rapid poison.
Heavy
Improves Strength scaling.
Sharp
Improves Skill scaling.
Cold
Improves Arcane scaling.
Warm
Improves Bloodtinge scaling.
Odd
Adds flat damage rather than percentage (applies to Tempering, Fire, Bolt, Arcane and Bloodtinge).
Elemental-damage gems swap physical damage for fire/bolt/arcane and scale with Arcane; scaling gems (Heavy, Sharp, Cold, Warm) change how much Strength, Skill, Arcane or Bloodtinge count.