[Solved] Clouds, depending on cloud type, altitude, and thickness, can either heat or cool the Earth. Tight Folds: Rock layers that have been bent very closely together, typically as a result of high pressure, forming narrow and sharp folds. Cleavage: A property of minerals that allows them to break along smooth, flat surfaces, determined by the mineral's crystal structure. Columnar Joints: Natural formations resulting from the cooling and cracking of volcanic rock into nearly hexagonal columns. Finely Crystalline: Describes a rock texture that consists of small, closely-packed crystals not easily visible to the naked eye.