The essential trace element silica is made up of two of the most abundant elements in the Earth's crust: silicon and oxygen. Silica is easily recognised in nature, as you see it in quartz crystals. The combination of these two elements is also called the beauty mineral, because of its direct effect on collagen production. Taking a little inspiration from nature itself, Crystal Colloidals unique manufacturing process is able to give you 300 PPM of colloidal silica in its purest form, composed of silica particles of 6 nanometres. Packaged in pharmaceutical-grade glass. Unlike ionic products, Crystal Colloidals Zinc is very stable, not light sensitive, and does not need to be refrigerated after opening. Do not freeze, the colloid will break! Sold in 250 ml and 1000 ml. When the smallest dosage (5 ml. per day) is used, a 1000 ml bottle lasts 200 days and 66 days when the highest dosage (15 ml. per day) is used. The actual dosage will vary according to individual needs.