Each impact-resistant 2 mL tube contains 2 mm yellow zirconia beads and a 4 mm black ceramic sphere. Matrix I tubes have clear caps. Zirconium oxide has very high density and high tensile strength and hardness, and is effective at breaking very tough and hard samples, including organisms within a tough or dense exterior matrix. This is useful in applications such as isolation of intact organelles, and super-molecular structures where lysis conditions necessitate high impaction but low shearing. The 4 mm ceramic sphere provides very high inertia for lysis by impaction of tough chitin/protein composites that comprise the exoskeleton of arthropods and crustaceans. Matrix I can also be used for dry grinding fungal spores to isolate RNA and Proteins.