Earth Clinic Colloidal Silver is .9999 pure silver nanoparticles in the colloid form. It is a TRUE colloidal silver, which means it is made of silver particles and not silver ions. Authentic colloidal silver of 20ppm is a light yellow, baby shampoo color. High bioavailability because of the nanometer-sized particles. It is an all-natural mineral supplement. Colloidal silver is made with the highest purity, alkaline water, with no potentially dangerous protein products. Earth Clinic Colloidal Silver will not cause argyria, a blue discoloration of the skin caused by silver protein products. Colloidal silver does not require refrigeration after opening. Infinite shelf life. Colloidal silver concentration is 20 ppm minimum. Do not let colloidal silver freeze. If this product freezes, the silver particles will fall out of suspension, agglomerate at the bottom, and the product will lose potency.