The streak of gypsum

Answer 1

White

Answer 2

Gypsum streaks typically appear as thin white or light gray streaks on surfaces such as walls or ceilings. These streaks can be caused by water seepage or moisture, which results in the gypsum material absorbing and spreading throughout the surface. To address gypsum streaks, it is important to first identify and fix the source of the moisture to prevent further streaking and damage. Cleaning the affected area with a mild detergent solution and allowing it to dry thoroughly can help remove existing streaks.