Optical Grade Calcium Carbonate from Canada
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 — Canada → United States
10%
Rate breakdown
9903.05.2910%Section 301 (forced labor) — additional 10% ad valorem on products of Canada
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