What exactly causes the Yellow Spring to be yellow? In a nutshell, iron.
A spring is defined as water overflowing from an aquifer. In this particular spring, the water underground is clear, but turns yellow when it hits the air. The iron in the water becomes rust when exposed to air, and turns into the well-known yellowish orange color that gave Yellow Springs its name. Experts theorize the water may run through an iron deposit underground (called a vugg) or the geology of the area could just contain excess iron.
