Yes, if the light is magical
Darkness says
A creature with darkvision can't see through this darkness, and nonmagical light can't illuminate it.
If any of this spell's area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.
Only nonmagical light cannot illuminate the darkness. Magical light therefore can.
Only spells of 2nd level or lower are dispelled when their light overlaps the darkness. Higher level spells are not, and will illuminate it. Magic items that shed light are not spells, and therefore are not dispelled. Only if such an item is casting a spell of 2nd or lower level creating the light, then that spell will be dispelled.
Spells do what they say they do — nothing else.
The question then is, does light from a magical source automatically count as magical light?
Magic items
Is the light produced by a magic item magical, or is it mundane light created by a magical source? The Sage Advice Compendium provides a checklist to see if something is magical:
- Is it a magic item? The light itself is not an item, so no.
- Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description? Only for those items creating spell effects, not for something like a mooblade, or flame tongue. The light from spells is explicitly not suppressed, but subject to being dispelled.
- Is it a spell attack? No
- Is it fueled by the use of spell slots? No
- Does its description say it’s magical? The moonlight of a moonblade is not described as magical (it does not say "magical moonlight")
By these criteria, the light of a moonblade would not qualify as magical. The magic item would need to say explicitly that it creates magical light.
This conclusion differs from the overwhelming community view in
Does Lightbringer illuminate or dispel the Darkness spell? and What is considered magical light for the purposes of the Darkness spell?, where the most upvoted answers both take the position that light created by a magic item is magical.
Artificer features
The artificer class description says:
You then touch a Tiny nonmagical object as an action and give it one of the following magical properties of your choice.
- The object sheds bright light in a 5-foot radius and dim light for an additional 5 feet.
The property of shedding light here is explicitly described as magical. However, that still could allow for magical shedding of mundane light.
Because this light is not caused by a spell or spell slots, and the light itself is not described as magical, this again would mean it is not, contrary to the widely preferred interpretation.
P.S A comment requested an example for non-spell magical light. One such example is the Armorer Artificer's Perfected Armor feature which for the Infiltrator option states:
Any creature that takes lightning damage from your Lightning Launcher glimmers with magical light until the start of your next turn.
Such a creature would illuminate the darkness. However, none of the weapons in the DMG, Tasha's, or Xanathar's say explicitly that they shed magical light, so if you'd follow a strict reading of the checklist for what is magical, none of them would illuminate darkness, against widely held community preferences.
