Optical Grade Calcium Carbonate from China
High-purity, low-birefringence calcium carbonate crystals for optical polishing compounds and lens manufacturing aids, under HTS 2836.50.00.00. Synthetic single crystals available.
Duty Rate — China → United States
37.5%
Rate breakdown
9903.88.0325%Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
9903.05.3112.5%Section 301 (forced labor) — additional 12.5% ad valorem on products of China
Import Tips
• Provide X-ray diffraction confirming calcite crystal structure
• Test for inclusions (<10 ppm) affecting optical clarity
• Package in inert atmosphere to prevent CO2 absorption/hydration