Verses with the word blackness in the Old Testament (4 verses):

Job 3:5
Let darkness and the shadow of death stain it; let a cloud dwell upon it; let the blackness of the day terrify it.

Isaiah 50:3
I clothe the heavens with blackness, and I make sackcloth their covering.

Joel 2:6
Before their face the people shall be much pained: all faces shall gather blackness.

Nahum 2:10
She is empty, and void, and waste: and the heart melteth, and the knees smite together, and much pain is in all loins, and the faces of them all gather blackness.