The word(s) "dark" appears 46 time(s) in 41 verse(s) in Quran in Mohsin Khan translation.

(31) It is He Who sends down manifest Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) to His slave (Muhammad صلى الله عليه وسلم) that He may bring you out from darkness into light. And verily, Allah is to you full of kindness, Most Merciful.

(32) (And has also sent to you) a Messenger (Muhammad صلى الله عليه وسلم), who recites to you the Verses of Allah (the Qur'an) containing clear explanations, that He may take out those who believe and do righteous good deeds, from the darkness (of polytheism and disbelief) to the light (of Islamic Monotheism). And whosoever believes in Allah and performs righteous good deeds, He will admit him into Gardens under which rivers flow (Paradise) to dwell therein forever. Allah has indeed granted for him an excellent provision.

(33) So the (garden) became black by the morning, like a pitch dark night (in complete ruins).

(34) And some faces, that Day, will be Basirah (dark, gloomy, frowning, and sad),

(35) And We have made the night as a covering (through its darkness),

(36) Its night He covers with darkness and its forenoon He brings out (with light)

(37) darkness will cover them.

(38) And by the night and whatever it gathers in its darkness,

(39) And then makes it dark stubble.

(40) By the night when it darkens (and stand still).