The #20 CO is a Natural Quartz product for plaster finishes. The #20 CO from our Colorado plant offers a closer source to west coast markets for natural aggregates and is whiteish in color. Its grade size is similar to our T-Grade material. Estes Quartz is sold as a site mix product. The advantages of site mix allow you to customize finishes to customer specifications, avoid lot # matching issues with pre-mixed products, and offers savings over pre-mixed products. The #20 CO contains small amounts of mica flakes that provide a brilliant sparkle to your plaster finishes.