The T-Grade HP Black is a Quartz product for plaster finishes. T-Grade HP Black from our Colorado plant offers a closer source to west coast markets. Specialty Graded T-Grade from the Estes Colorado plant allows you to add the right amount of aggregate to your plaster finish to get your desired finish. 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. T-Grade HP Black from Colorado plant contains small amounts of mica flakes that provide a brilliant sparkle to your plaster finishes.