From Dark and Darker Wiki

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<br>
<br>
20/156 unique drops on the hoard are artifacts
20/156 unique drops on the hoard are artifacts
<br>
12.821% Chance if you hit a unique you get an artifact
12.821% Chance if you hit a unique you get an artifact
<br>
So overall the Hoard has a 0.0128% chance to drop an artifact per hit
So overall the Hoard has a 0.0128% chance to drop an artifact per hit
<br>
<br>
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Skull Key room loose weapon DropRate is 37.5% Epic, 52.5% Legendary, 10% Unique
Skull Key room loose weapon DropRate is 37.5% Epic, 52.5% Legendary, 10% Unique
<br>
<br>
Skull key room  
Skull key room
<br>
20/43 unique drops are Artifacts
20/43 unique drops are Artifacts
<br>
41.666% Chance if you hit a unique it will be an artifact
41.666% Chance if you hit a unique it will be an artifact
<br>
So overall the Skull room has a 4.6512% chance to drop an artifact per hit
So overall the Skull room has a 4.6512% chance to drop an artifact per hit
<br>
<br>
<br>
<br>
Mystic Gem room weapon spawn is 75% Epic, 21% Legendary, 4% Unique
Mystic Gem room weapon spawn is 75% Epic, 21% Legendary, 4% Unique
<br>
20/43 unique drops at the mystic gem room are artifacts
20/43 unique drops at the mystic gem room are artifacts
<br>
46.512% Chance if you hit a unique it will be an artifact
46.512% Chance if you hit a unique it will be an artifact
<br>
So overall the Mystic Gem has a 1.8605% chance to drop an artifact per hit
So overall the Mystic Gem has a 1.8605% chance to drop an artifact per hit
<br>
<br>
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<br>
<br>
20/43 unique drops at the Dual Boss Treasure room are artifacts
20/43 unique drops at the Dual Boss Treasure room are artifacts
<br>
46.512% Chance if you hit a unique it will be an artifact
46.512% Chance if you hit a unique it will be an artifact
<br>
So overall the Dual Boss Treasure (weapon) room has a 0.233% chance to drop an artifact per hit
So overall the Dual Boss Treasure (weapon) room has a 0.233% chance to drop an artifact per hit
<br>
<br>
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<br>
<br>
(1 - ((1055/1075)^15)) x100 = C is the formula for 15 runs at the mystic gem room,
(1 - ((1055/1075)^15)) x100 = C is the formula for 15 runs at the mystic gem room,
<br>
After 15 tries you chance of getting 1 or more Artifacts from the room would be 24.55%.
After 15 tries you chance of getting 1 or more Artifacts from the room would be 24.55%.
<br>
<br>

Revision as of 06:52, 2 April 2024

Weapon Data is currently up to date for: Patch:6.4#Hotfix 46Last updated on the current Patch/Hotfix. Information is up to date.

Artifacts are base weapons that have special models, names, stats, and effects.

Arming Sword

Kuma's Claw
Kuma's Claw.png

-
Move Speed -20
-
-
Physical Weapon Damage 38~39
-
-
Up to 5 extra enchantments
-
-
+15 additional Dark Magical Damage (100% scaling).
-
Required Class:
Armor Type:
Sword
Slot Type:
Main-Hand
Hand Type:
One Handed
Hitbox:
54x11.17x1.26
1x3InvSlot.jpg
Adventure Points
Item Achieve:
90
Forged from the flames of a mighty black dragon, this sword claws at the target's soul, inflicting lethal damage.
Drop Table
Name Type Count Chance
Skeleton Warlord#Elite Monster 1 0.0581%
Weapon SkullRoom Loose Loot 1 0.0488%

Falchion

Kuma's Fang
Kuma's Fang.png

-
Move Speed -25
-
-
Physical Weapon Damage 49~51
-
-
Up to 5 extra enchantments
-
-
+15 additional Dark Magical Damage (100% scaling).
-
Required Class:
Armor Type:
Sword
Slot Type:
Main-Hand
Hand Type:
One Handed
Hitbox:
50.67x10.31x1.73
1x3InvSlot.jpg
Adventure Points
Item Achieve:
90
Seems the great black dragon has lost a tooth... No matter, it will continue its bloody purpose.
Drop Table
Name Type Count Chance
Skeleton Warlord#Elite Monster 1 0.0581%
Weapon SkullRoom Loose Loot 1 0.0488%

Longsword

Fulgor
Fulgor.png

-
Move Speed -30
-
-
Physical Weapon Damage 49~51
-
-
Up to 5 extra enchantments
-
-
If you hit an enemy, summons a thunderbolt to deal 20 additional magic damage (100% scaling).
-
Required Class:
Armor Type:
Sword
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
80.41x17.14x2.42
1x4InvSlot.jpg
Adventure Points
Item Achieve:
120
Long ago, a King was gifted this artifact by someone who valued his sense of dream, justice, love and kindness, hoping to help him carve these principles into the world.
Drop Table
Name Type Count Chance
Skeleton Warlord#Elite Monster 1 0.0093%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Rapier

Viola
Viola.png

-
Move Speed -13
-
-
Physical Weapon Damage 33~34
-
-
Up to 5 extra enchantments
-
-
Hitting an enemy deals 10 additional magic damage (100% scaling), and frostbites them for 2 seconds.
-
Required Class:
Armor Type:
Sword
Slot Type:
Main-Hand
Hand Type:
One Handed
Hitbox:
56.13x13.21x5.92
1x3InvSlot.jpg
Adventure Points
Item Achieve:
90
The chill of winter flows in the wake of this icy blade. Gifted from the Winter Fae who wanted to prove there is nothing stronger than the cold bite of their domain.
Drop Table
Name Type Count Chance
Skeleton Warlord#Elite Monster 1 0.0093%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Stiletto Dagger

Deathbloom
Deathbloom.png

-
Move Speed -10
-
-
Physical Weapon Damage 28~29
-
-
Up to 5 extra enchantments
-
-
Inflicting damage causes a death flower to bloom. After 3 blooms, the death blossom explodes dealing 30 bonus magic damage (0% scaling).
-
Required Class:
Armor Type:
Dagger
Slot Type:
Off-Hand
Hand Type:
One Handed
Hitbox:
25.72x4.55x2.3
1x2InvSlot.jpg
Adventure Points
Item Achieve:
60
Thou love me, thou love me not... Thou love me, thou love me not...
Drop Table
Name Type Count Chance
Ghost King#Elite Monster 1 0.0086%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Morning Star

Pulverizing Prayer
Pulverizing Prayer.png

-
Move Speed -25
-
-
Physical Weapon Damage 47~49
-
-
Armor Penetration 15%
-
-
Up to 5 extra enchantments
-
-
Crushes the enemy's armor with each hit, reducing the target's physical damage reduction by flat -25%. Stacks up to 3 times, lasts 10 seconds.
-
Required Class:
Armor Type:
Mace
Slot Type:
Main-Hand
Hand Type:
One Handed
Hitbox:
42.35x9.5x9.4
1x3InvSlot.jpg
Adventure Points
Item Achieve:
90
Gifted to a holy fighter long ago by a demi-god, proving faith is also a powerful weapon, crushing all non-believers.
Drop Table
Name Type Count Chance
Skeleton Warlord#Elite Monster 1 0.0093%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Quarterstaff

Stinky Stick
Stinky Stick.png

-
Move Speed -30
-
-
Physical Weapon Damage 42~43
-
-
Up to 5 extra enchantments
-
-
Hitting a target has a chance(15%) to emit a poisonous cloud that causes 6 magical damage (60% scaling) per second. Holding this stick makes you immune to poison cloud.
-
Required Class:
Armor Type:
Mace, Staff
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
86.59x3.91x3.43
1x5InvSlot.jpg
Adventure Points
Item Achieve:
150
Pee-eewh! This thing reeks....
Drop Table
Name Type Count Chance
Ghost King#Elite Monster 1 0.0086%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Halberd

Cinder
Cinder.png

-
Move Speed -50
-
-
Physical Weapon Damage 62~64
-
-
Up to 5 extra enchantments
-
-
Hitting an enemy deals 10 additional magic damage (100% scaling) and burns them for 9 magic damage (50% scaling) over 3 seconds.
-
Required Class:
Armor Type:
Polearm
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
119.7x15.84x2.14
2x5InvSlot.jpg
Adventure Points
Item Achieve:
300
It will be difficult to keep track of your kill count for they have all been reduced to a pile of ash.
Drop Table
Name Type Count Chance
Ghost King#Elite Monster 1 0.0086%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Battle Axe

Echo of Screams
Echo of Screams.png

-
Move Speed -40
-
-
Physical Weapon Damage 59~61
-
-
Up to 5 extra enchantments
-
-
Deals 20 true magical damage (0% scaling) to the target and causes the victim to hear their screams, deafening them for 3 seconds
-
Required Class:
Armor Type:
Axe
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
65.48x14.71x2.79
2x4InvSlot.jpg
Adventure Points
Item Achieve:
240
An ancient axe imbued with the screams of fallen enemies, granting its wielder a deadly strength that comes from the echoes of the past.
Drop Table
Name Type Count Chance
Ghost King#Elite Monster 1 0.0086%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Double Axe

Life after Death
Life after Death.png

-
Move Speed -40
-
-
Physical Weapon Damage 63~65
-
-
Up to 5 extra enchantments
-
-
When receiving a lethal attack, HP becomes 1 and becomes invincible for 2 seconds. This effect can only be triggered once during an adventure.
-
Required Class:
Armor Type:
Axe
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
72.75x19.43x2.64
2x4InvSlot.jpg
Adventure Points
Item Achieve:
240
Death comes for us all one day...
Is today that day?
Drop Table
Name Type Count Chance
Ghost King#Elite Monster 1 0.0086%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Felling Axe

Soulscraper
Soulscraper.png

-
Move Speed -35
-
-
Physical Weapon Damage 56~58
-
-
Up to 5 extra enchantments
-
-
Each time you deal damage, you absorb an opponent's soul, gaining 5 Strength for 8 seconds. This effect stacks up to 3 times.
-
Required Class:
Armor Type:
Axe
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
56.51x13.29x2.18
2x4InvSlot.jpg
Adventure Points
Item Achieve:
240
Through a bond that transcended realms, a guardian of souls granted a mortal companion this enchanted axe.
Drop Table
Name Type Count Chance
Ghost King#Elite Monster 1 0.0086%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Horseman's Axe

Famine
Famine.png

-
Move Speed -30
-
-
Physical Weapon Damage 38~39
-
-
Up to 5 extra enchantments
-
-
Hitting the target will render them unable to receive any healing effects for 20 seconds.
-
Required Class:
Armor Type:
Axe
Slot Type:
Main-Hand
Hand Type:
One Handed
Hitbox:
47.54x10.57x1.58
1x3InvSlot.jpg
Adventure Points
Item Achieve:
90
This enchanted axe is crafted by infusing the blood and essence from the third of the legendary Four Horsemen.
Drop Table
Name Type Count Chance
Ghost King#Elite Monster 1 0.0086%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Longbow

Nipalan
Nipalan.png

-
Move Speed -50
-
-
Physical Weapon Damage 48~49
-
-
Up to 5 extra enchantments
-
-
Pushes the hit target back.
-
Required Class:
Armor Type:
Bow
Slot Type:
Main-Hand
Hand Type:
Two Handed
Quiver Size:
6
Hitbox:
93.7x37.48x5.93
1x4InvSlot.jpg
Adventure Points
Item Achieve:
120
A bow crafted by a legendary tribe of warriors known as the Penobscots. So terrifyingly strong it knocks back their foes.
Drop Table
Name Type Count Chance
Lich#Elite Monster 1 0.0094%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Recurve Bow

Pestilence
Pestilence.png

-
Move Speed -40
-
-
Physical Weapon Damage 41~42
-
-
Up to 5 extra enchantments
-
-
Hitting the target inflicts a disease that deals 20 magic damage (50% scaling) over 3 seconds.
-
Required Class:
Armor Type:
Bow
Slot Type:
Main-Hand
Hand Type:
Two Handed
Quiver Size:
8
Hitbox:
70.24x35.45x19.56
1x3InvSlot.jpg
Adventure Points
Item Achieve:
90
Capable of spreading poison that will have it's victims begging for death, this cursed bow once belonged to first of the legendary Four Horseman.
Drop Table
Name Type Count Chance
Lich#Elite Monster 1 0.0094%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Survival Bow

Elven Bow of Truth
Elven Bow of Truth.png

-
Move Speed -30
-
-
Physical Weapon Damage 30~31
-
-
Up to 5 extra enchantments
-
-
When shooting a bow, the action speed is 10% faster and the arrow flies in a straight line.
-
Required Class:
Armor Type:
Bow
Slot Type:
Main-Hand
Hand Type:
Two Handed
Quiver Size:
10
Hitbox:
61.51x35.45x17.26
1x3InvSlot.jpg
Adventure Points
Item Achieve:
90
A bow made by the elves by forging the branches of the tree of truth.
Drop Table
Name Type Count Chance
Lich#Elite Monster 1 0.0094%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Heater Shield

Aegis
Aegis.png

-
Armor Rating 36~38
-
-
Move Speed -15
-
-
Up to 5 extra enchantments
-
-
Can deflect projectile spells while in defensive stance. After the reflection is triggered, you remain able to reflect for 3 seconds, and cannot reflect again for 20 seconds after performing a spell reflection.
-
Required Class:
Armor Type:
Shield
Slot Type:
Off-Hand
Hand Type:
One Handed
Hitbox:
39.37x31.34x10.33
2x3InvSlot.jpg
Adventure Points
Item Achieve:
180
Crafted by a powerful and mysterious being to aid in eliminating magic users. He saw wizards lust for magic, fearing they would grow too powerful.
Drop Table
Name Type Count Chance
Skeleton Warlord#Elite Monster 1 0.0093%
Treasure Hoard#Goblin Caves HR Container 1 0.0006%
Treasure Hoard#Crypt HR Container 1 0.0006%
Treasure Hoard#Inferno HR Container 1 0.0006%
Treasure Hoard Container 1 0.0006%
DualBossWeapon HR Loose Loot 1 0.0116%
Weapon GoldenRoom Loose Loot 1 0.0233%
Weapon MysticalTreasureRoom Loose Loot 1 0.093%
Weapon SkullRoom Loose Loot 1 0.2326%

Buckler

Delirium
Delirium.png

-
Armor Rating 29~30
-
-
Move Speed -7
-
-
Up to 5 extra enchantments
-
-
When held in hand, maximum health is reduced by 10%, but regenerates 1 health per second (0% Scaling).
-
Required Class:
Armor Type:
Shield
Slot Type:
Off-Hand
Hand Type:
One Handed
Hitbox:
25.77x25.77x5.54
2x2InvSlot.jpg
Adventure Points
Item Achieve:
120
Created by a mad alchemist, using dragons blood in some of his creations. Beware, its side effects can be just as potent as they are perilous.

DropTable:Buckler 7

Spellbook

Spellweaver
Spellweaver.png

-
Magical Damage 8
-
-
Move Speed -10
-
-
Up to 5 extra enchantments
-
-
Successfully casting a spell increases your casting speed by 5%, up to 5 times. The effect lasts for 3 seconds and is reset each time it increases.
-
Required Class:
Armor Type:
MagicStuff
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
12.75x21.25x5.55
2x2InvSlot.jpg
Adventure Points
Item Achieve:
120
A rare spellbook pulsing with arcane energy, whispering ancient secrets in an unknown language. Rumored to have been taken from a mysterious land only accessible through special portals.

DropTable:Spellbook 7

Magic Staff

Illusory
Illusory.png

-
Move Speed -20
-
-
Physical Weapon Damage 38~39
-
-
Magical Damage 10
-
-
Up to 5 extra enchantments
-
-
A successful spell cast makes the user invisible for 2 seconds and leaves the user's illusion temporarily.
-
Required Class:
Armor Type:
MagicStuff, Staff
Slot Type:
Main-Hand
Hand Type:
Two Handed
Hitbox:
81.86x6.35x3.84
1x4InvSlot.jpg
Adventure Points
Item Achieve:
120
Rumored to be crafted by a powerful yet mischievous trickster from another realm, who delighted in confusing and outsmarting their enemies.

DropTable:Magic Staff 7

Crystal Ball

Zirkzi's Eye
Zirkzi's Eye.png

-
Magical Damage 8
-
-
Physical Weapon Damage Add 3
-
-
Move Speed -15
-
-
Up to 5 extra enchantments
-
-
If the spell hits the target, Death's Gaze deals an additional 2 True Magical Damage (0% scaling) to the enemy.
-
Required Class:
Armor Type:
MagicStuff
Slot Type:
Off-Hand
Hand Type:
One Handed
Hitbox:
8.85x8.85x8.85
2x2InvSlot.jpg
Adventure Points
Item Achieve:
120
Unable to defeat a hopelessly powerful demi-god, an ancient sorcerer sacrificed his life to seal one of the demi-god's eyes in a crystal ball.

DropTable:Crystal Ball 7

Methods of obtaining Artifacts


Hoard
20/156 unique drops on the hoard are artifacts
12.821% Chance if you hit a unique you get an artifact
So overall the Hoard has a 0.0128% chance to drop an artifact per hit

Skull Key room loose weapon DropRate is 37.5% Epic, 52.5% Legendary, 10% Unique
Skull key room
20/43 unique drops are Artifacts
41.666% Chance if you hit a unique it will be an artifact
So overall the Skull room has a 4.6512% chance to drop an artifact per hit

Mystic Gem room weapon spawn is 75% Epic, 21% Legendary, 4% Unique
20/43 unique drops at the mystic gem room are artifacts
46.512% Chance if you hit a unique it will be an artifact
So overall the Mystic Gem has a 1.8605% chance to drop an artifact per hit

Double Boss room ground loot is 91.5% Epic, 8% Legendary, 0.5% Unique. (for the weapon)
20/43 unique drops at the Dual Boss Treasure room are artifacts
46.512% Chance if you hit a unique it will be an artifact
So overall the Dual Boss Treasure (weapon) room has a 0.233% chance to drop an artifact per hit

For the chance at an Artifact appearing after multiple trials is
(1 - ((V)^N)) x100 = C
V is chance of failure, N is times you hit the door, and C is your answer in percentage format of getting 1 or more artifacts
Example
(1 - ((1055/1075)^15)) x100 = C is the formula for 15 runs at the mystic gem room,
After 15 tries you chance of getting 1 or more Artifacts from the room would be 24.55%.
15 runs of skull key would be (1 - ((410/430)^15)) x100 = C
51.052% of getting one or more Artifacts