Revelation 6:12 describes the sun becoming black 'as sackcloth of hair' during the sixth seal judgment. This imagery draws on the Old Testament practice of wearing rough garments made from goat or camel hair as a sign of mourning or repentance. The darkening of the sun to the color and texture of such material suggests cosmic mourning—even the heavens grieve at the judgment being poured out. The reference to hair emphasizes the coarse, dark nature of the fabric, intensifying the apocalyptic vision of creation itself reacting to divine wrath.