Loading...
U.S. exports of unworked tubes of fused quartz or fused silica (HS 700231) totaled $15.0M in July 2026.
Importers of Unworked Tubes of Fused Quartz or Fused Silica paid $908K in duties in July 2026 — an effective duty rate of 11% on $8.1M in dutiable value, based on actual customs collections rather than the published tariff schedule. Unworked Tubes of Fused Quartz or Fused Silica imports of $9.2M in July 2026 ran 19% above the year-to-date monthly average of $7.7M.
Last updated: July 2026 dataFused quartz and fused silica tubes are high-purity industrial intermediates critical to semiconductor diffusion furnaces, UV lamp manufacturing, and laboratory apparatus — applications that demand the material's exceptional thermal stability and low thermal expansion. All US imports of this form fall under a single 10-digit line, 7002310000. Germany leads supply, with China and the United Kingdom also prominent sources, reflecting the specialized capital investment required to produce consistent-diameter, high-purity tubing.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
234 shipments/mo
Importers should evaluate whether applicable Section 301 tariffs apply to Chinese-origin fused silica tubes under this heading. The duty impact can be significant given the high unit value of precision fused-silica tubing, so a binding ruling or broker review is advisable before committing to a China-origin supply chain.
Customs may request a manufacturer's material certificate or spectroscopic analysis confirming silicon dioxide purity and the fusion process. Fused quartz and fused silica are classified here (700231), while other low-expansion glass tubes with a linear coefficient not exceeding 5×10⁻⁶ per Kelvin fall under a separate heading (700232). Providing clear compositional documentation at entry avoids reclassification.
HSChapter 70
Supplier Network
Get discovered by U.S. importers searching for HS 700231 — Unworked Tubes of Fused Quartz or Fused Silica. Be the first supplier listed.
Subheading 1 of 5 in heading 7002
Subheading 700231 · $9.2M of $16.8M
ImportsExports
Imports
$9.2MYoY · Pro
Exports
$15.0MYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 7002310000 | Tubes of Fused Quartz or Oth Fsd Silica, Unworked | $9.2M | 9.85% | 88.34% | $908K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 7002310000 | Tubes of Fused Quartz or Oth Fsd Silica, Unworked | $15.0M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
Exports · July 2026
destination
China and Mexico together take 43% of it.
customs district
origin
entry
rate provision · imports
11.4% enters free of duty; the effective duty rate is 9.85%.