Deleterious organic materials in fine aggregates can be easily detected with the Organic Impurities Test, a simple, widely-used test. Samples are mixed in a special graduated colorless glass bottle with a 3% sodium hydroxide solution, then allowed to stand for 24 hours. If the color of the supernatant liquid above the test sample is darker than a standard reference color, organic compounds may be present and further testing should be done before approval. Includes sodium hydroxide pellets, Reagent grade sodium hydroxide pellets can be purchased seperately to meet ASTM standards.