Kieselguhr Insulating Brick from Mexico
Insulating ceramic brick produced from kieselguhr (diatomite), offering excellent thermal resistance for boiler linings and high-heat applications. Classified under HTS 6901.00.00.00 due to its composition from siliceous fossil meals fired after shaping.
Duty Rate — Mexico → United States
10%
Rate breakdown
9903.05.5510%Except for products described in headings 9903.05.85–9903.05.92 and 9903.05.94, articles the product of Mexico, as provided for in U.S. note 52 to this subchapter
Import Tips
• Include lab test results showing water absorption and silica content typical of diatomaceous earth
• Ensure marking indicates 'diatomite' or 'kieselguhr' composition for customs verification
• Avoid mixing with clay products in shipments to prevent average absorption calculations affecting classification