Silica Gel Blue semi-transparent glassy substance containing an indicator as “Cobalt Chloride” a heavy metal salt. When free from moisture the Granules or beads are dark blue in color. … Blue Silica Gel is also know as Indicating Silica Gel, Self Indicating Silica Gel, Blue Desiccants, Moisture absorber.

Chemical Formula: SiO2+H2O+CoCl2