'Black' in the Bible

nor by thy head mayest thou swear, because thou art not able one hair to make white or black;

And when he opened the third seal, I heard the third living creature saying, 'Come and behold!' and I saw, and lo, a black horse, and he who is sitting upon it is having a balance in his hand,

And I saw when he opened the sixth seal, and lo, a great earthquake came, and the sun became black as sackcloth of hair, and the moon became as blood,