U.S. imports of Unworked Tubes of Fused Quartz or Fused Silica (HS 700231) totaled $8.7M in September 2026, imported from 22 countries.
Importers of Unworked Tubes of Fused Quartz or Fused Silica paid $1.0M in duties in September 2026, an average duty rate of 11.61% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule.
Last updated: September 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.
224 import shipments a month
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.
Trade Directory
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Subheading 1 of 5 in heading 7002
Subheading 700231 · $8.7M of $21.0M
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Imports for consumption | Average duty rate | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 7002310000 | Tubes of Fused Quartz or Oth Fsd Silica, Unworked | $10.1M | 11.83% | 99.84% | $1.2M |
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 | $15.9M |
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.
ImportsExports
Imports
$8.7MYoY · free account
Exports
—YoY · free account
12-mo low · imports
Low · free accountOver the twelve months to September 2026, the U.S. imported $97.4M of Unworked Tubes of Fused Quartz or Fused Silica.
Through September 2026 · exports 11 of 12 months reported. Source: U.S. Census Bureau.
Imports · September 2026
origin
Germany and China together supply 96% of it. China pays 37.4% duty; Germany 10.0%.
customs district
destination
entry
rate provision · imports
0.1% enters free of duty; duty collected equals 11.61% of imports for consumption.