Rochelle Salt for Piezoelectric Crystals from Mexico
Specialty potassium sodium tartrate grown into large single crystals for piezoelectric applications in early microphones and transducers. Falls precisely under HTS 2918.13.3000 as the named Rochelle salt, a tartaric acid salt with defined chemical structure per Chapter 29.
Duty Rate — Mexico → United States
10%
Rate breakdown
9903.05.5510%Section 301 (forced labor) — additional 10% ad valorem on products of Mexico
Import Tips
• Include crystal growth specifications and piezoelectric constant measurements for technical validation
• Ship in temperature-controlled containers (15-25°C) to prevent crystal twinning or defects
• Avoid classification disputes by providing structural formula confirming KNaC4H4O6·4H2O composition