Orange Crystal Silica Gel is semi-transparent glassy crystals used as moisture absorbent. It appears Orange in color. It also is known as self Indicating type Silica gel because When free from moisture the particles are dark orange. As they are put to use, the particles take up moisture, Silica Gel gradually turns Orange-Yellow & then to green and gives a ready indication that it has done or it's saturated. Its work and requires replacement or regeneration. In fact, it is mainly used as an indicator for the extent of dehumidification and moisture absorption in the sealed vessel.