The resulting item will always be different than the original item.
The resulting item will always be of the same item class (e.g. one-handed sword), and occupy the same number of inventory space in terms of size (e.g. a 3x2 SilverbranchSilverbranch Crude BowBow Physical Damage: (9-10) to (23.4-26) Critical Strike Chance: 5.00% Attacks per Second: 1.54+1 to Level of SocketedBow Gems (80-100)% increased Physical Damage 10% increased Attack Speed Gain 10 Mana per Enemy Killed +30 to Accuracy Rating"The wild takes care of its own." - Hyrri of the Karui cannot roll into a 4x2 Iron CommanderIron Commander Death BowBow Physical Damage: (36-40) to (89-97) Critical Strike Chance: (6.50-7.50)% Attacks per Second: (1.37-1.44)Requires Level 32, 107 Dex(30-50)% increased Critical Strike ChanceAdds (8-12) to (16-24) Physical Damage (14-20)% increased Attack Speed (14-20)% increased TotemLife (14-20)% increased Totem Placement speed Siege Ballista has +1 to maximum number of Summoned Totems per 200 Dexterity Adds 1 to 3 Physical Damage to Attacks per 25 DexterityThe Eternals commanded an army that need not eat, sleep, or breathe without the usual depravities of necromancy.).
Ancient Orbs do not change the inventory size of an item, so 4x2-sized "tower shields" for example stay within that group.[1]
Items are completely reforged when an Ancient Orb is applied. Sockets and links are randomized. Influences, enchantments, and other special item traits are lost when rerolling.
Ancient Orbs can roll certain outcomes (e.g. Unique Talismans or Kalandra's TouchKalandra's Touch RingReflects your other RingMirroredOn one hand, you have a choice. On the other, you have its twin.) which are no longer modifiable using Ancient Orbs, preventing them from being rolled over accidentally.
Unique Jewels, Flasks or Maps cannot be re-rolled, although it was possible to do so prior to version 3.20.0.
Unique flasks did not discern between life, mana, hybrid or utility flasks.
Unique cluster jewels and Abyss jewels were considered in the same group as other regular jewels; no core drop pool unique versions of cluster jewels or abyss jewels exist, however, so this is a one-way change to a regular jewel base type.[2]
Item level mechanics
Unlike the Orb of ChanceOrb of ChanceStack Size: 20Upgrades a normal item to a random rarityRight click this item then left click a normal item to apply it., Ancient Orbs are influenced by the base item's item level to determine the possible outcomes. In general, the item level must be equal to or higher than the drop level of the unique item; if no drop level is specified, this typically matches the unique's level requirement. Base items under ilvl 40 are treated as if the item is ilvl 40; this means that obtaining an item level 2 base item can roll any uniques for that item category and size that has a drop level of 40 or under.[3] For example:
Obtain a Lioneye's RemorseLioneye's Remorse Pinnacle Tower ShieldChance to Block: 30% Armour: (1307-1718) Movement Speed: -3%Requires Level 70, 159 Str+(20-30) to maximum Life(180-220)% increased Armour 20% increased Stun and Block Recovery +(160-180) to maximum Life 5% reduced Movement Speed -25 Physical Damage taken from Projectile Attacks +5% Chance to BlockMarceus' unblemished shield is a testament to his arrogance... and his fate. by redeeming The LionThe Lion5Lioneye ItemThe Eternals lauded his valour. The Karui relished his defeat. Yet the final thoughts of Marceus Lioneye were naught but lament for his pride. on a low level character, granting you a low ilvl shield (e.g. ilvl 2).
Because of the ilvl 40 buffer, using an Ancient Orb will cause it to randomly cycle between LycosidaeLycosidae Rawhide Tower ShieldChance to Block: (29-31)% Armour: (173-226) Movement Speed: -3%Requires Level 11, 33 Str+(10-20) to maximum Life+(120-160) to Armour +(30-40) to maximum Life Your hits can't be Evaded +(3-5)% Chance to Block Adds 250 to 300 Cold Damage to CounterattacksA true predator does not chase; It waits., Trolltimber SpireTrolltimber Spire Cedar Tower ShieldChance to Block: 25% Armour: (216-282) Movement Speed: -3%Requires Level 17, 47 Str+(20-30) to maximum Life(130-150)% increased Armour +(40-60) to maximum Life You and your Totems Regenerate 0.5% of Life per second for each Summoned Totem 15% increased Area of Effect for Skills used by Totems 0.5% of Damage dealt by your Totems is Leeched to you as LifeThe problem with working fresh trolltimber: by the time you've carved out one end, the other has sprouted fresh roots!, and Titucius' SpanTitucius' Span Reinforced Tower ShieldChance to Block: 23% Armour: (379-468) Movement Speed: -3%Requires Level 30, 76 Str+(10-20) to maximum Life(60-80)% increased Armour +(30-50) to maximum Life -(80-50) Physical Damage taken from Projectile Attacks 200% increased Armour against Projectiles +25% chance to Block Projectile Attack DamageA mighty bulwark, curved and strong A dauntless wall, against the throng All lance and arrow, knocked aside For rout of foe, for turn of tide..
The shield will never be able to turn back into a Lioneye's Remorse, which has a drop level of 73.
The influence of item level on Ancient Orb outcomes appears to have silently changed in an unknown patch, as it was once possible to Ancient Orb between a Lycosidae and Trolltimber Spire deterministically on an item level 27 4x2 shield, as Titucius' Span was not eligible at the time.
This method can be useful to limit the pool of outcomes to more reliably get a specific unique, or to target farm low item level corruption implicits on certain unique items. Divination cards can be used to reliably get low level item bases.
Item acquisition
Ancient Orb has restrictions on where or how it can drop.
Drops from Harbingers or Harbinger-related rewards.
Recipes
Ancient Orb can be created from the following recipes:
Amount
Part
Notes
Description
Meta
20
Ancient ShardAncient ShardStack Size: 20A stack of 20 shards becomes an Ancient Orb.
N/A
N/A
M
1
Foreboding IncubatorForeboding IncubatorStack Size: 10Adds incubated valuable Currency Shards or a Harbinger item to an equippable item Item drops after killing {0} monstersRight click this item then left click an item to apply it. The Incubated item drops after killing a specific number of monsters.
Requires ilvl 68 or above Incubator
valuable Currency Shards or Harbinger Item (random)
Can now only be dropped from Foreboding IncubatorsForeboding IncubatorStack Size: 10Adds incubated valuable Currency Shards or a Harbinger item to an equippable item Item drops after killing {0} monstersRight click this item then left click an item to apply it. The Incubated item drops after killing a specific number of monsters. of level 68 or higher.
SilverbranchSilverbranch
cannot roll into a 4x2 
Iron CommanderIron Commander
).
Kalandra's TouchKalandra's Touch
) which are no longer modifiable using Ancient Orbs, preventing them from being rolled over accidentally.
Orb of ChanceOrb of ChanceStack Size: 20Upgrades a normal item to a random rarityRight click this item then left click a normal item to apply it.
, Ancient Orbs are influenced by the base item's item level to determine the possible outcomes. In general, the item level must be equal to or higher than the drop level of the unique item; if no drop level is specified, this typically matches the unique's level requirement. Base items under ilvl 40 are treated as if the item is ilvl 40; this means that obtaining an item level 2 base item can roll any uniques for that item category and size that has a drop level of 40 or under.[3] For example:
Lioneye's RemorseLioneye's Remorse
by redeeming 
The Lion
The Lion
on a low level character, granting you a low ilvl shield (e.g. ilvl 2).
LycosidaeLycosidae
, 
Trolltimber SpireTrolltimber Spire
, and 
Titucius' SpanTitucius' Span
.
Ancient ShardAncient ShardStack Size: 20A stack of 20 shards becomes an Ancient Orb.
Foreboding IncubatorForeboding IncubatorStack Size: 10Adds incubated valuable Currency Shards or a Harbinger item to an equippable item