Is The Darkness Crystal legal in Standard, Modern, and Commander?

The Darkness Crystal is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Historic.

The Darkness Crystal

Q: What type of card is The Darkness Crystal?

The Darkness Crystal is a Legendary Artifact. Its oracle text reads: "Black spells you cast cost {1} less to cast. If a nontoken creature an opponent controls would die, instead exile it and you gain 2 life. {4}{B}{B}, {T}: Put target creature card exiled with The Darkness Crystal onto the battlefield tapped under your control with two additional +1/+1 counters on it."

Legendary Artifact

$3.97 ↗17 combosCommander, Modern

Black spells you cast cost less to cast.

If a nontoken creature an opponent controls would die, instead exile it and you gain 2 life.

, : Put target creature card exiled with The Darkness Crystal onto the battlefield tapped under your control with two additional +1/+1 counters on it.