Product classification
HS code for Fused silica tubes: 7002.31
Glass, unworked, in tubes, of fused quartz or other fused silica.
Classification of fused silica tubes under HS 7002.31
Fused silica tubes are classified under HS code 7002.31, which pertains to glass in tubes that is unworked and specifically made of fused quartz or other fused silica. The classification logic follows the material composition and the state of manufacture. Chapter 70 covers glass and glassware, and heading 7002 is dedicated to glass in balls, rods, or tubes, provided they have not been worked beyond simple cutting or surface treatment. The subheading 7002.31 is distinguished by the high silica content (typically over 99% SiO2), which gives the glass its unique thermal and optical properties, such as a low coefficient of thermal expansion and high UV transparency. If the tubes were further processed into specific laboratory instruments, they would move to heading 7017. However, in their primary, unworked tubular form, they remain in 7002. This classification is consistent with GRI 1 and 6, focusing on the literal description of the goods and their chemical purity. The distinction between fused silica and other types of glass (like borosilicate) is critical for determining the correct subheading.
- Covers
- Unworked fused quartz tubing
- Transparent fused silica tubes
- Opaque or translucent silica tubes
- High-purity quartz glass cylinders
- Fused silica capillary tubes (unworked)
- Also under 7002.31
- Heraeus Quartz
- Shin-Etsu Quartz
- Momentive Technologies
- QSIL
Codes often confused with 7002.31
Common mistake. Fused silica tubes are often misclassified under 7017.10, which covers laboratory, hygienic, or pharmaceutical glassware. The distinction lies in whether the tube is \"unworked.\" If the tube has been graduated, calibrated, or fitted with joints, it belongs in 7017. Another common error is 7002.32, which is for glass with a different coefficient of expansion (like borosilicate). Finally, if the silica is in fiber form, it must be classified under 7019 rather than 7002.
Top exporters and importers of HS 700231 (the code used for fused silica tubes), 2025
In 2025, the largest exporter of HS 700231 (the code used for fused silica tubes) in UN Comtrade data was the United States, with 43% of world exports; the largest importer in UN Comtrade data was the United States, with 19% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 700231, not only fused silica tubes.
Top exporters 2025 · share of world exports
- 1 United States $155M 43% of world exports
- 2 Germany $100M 28% of world exports
- 3 China $40M 11% of world exports
World total: $363M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 United States $97M 19% of world imports
- 2 Mexico $83M 17% of world imports
- 3 China $62M 12% of world imports
World total: $504M Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM code for fused silica tubes
Brazil classifies fused silica tubes under NCM 7002.31.00: HS 7002.31 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about fused silica tubes
What is the HS code for Fused silica tubes?
The HS code for Fused silica tubes is 700231 (Glass; unworked, in tubes, of fused quartz or other fused silica). The correct HS code for unworked fused silica tubes is 7002.31.
How do I classify Fused silica tubes for customs?
Fused silica tubes is classified under HS code 700231 — Glass; unworked, in tubes, of fused quartz or other fused silica. This is a 6-digit subheading level code.
What defines a tube as \"unworked\" for HS code 7002?
An unworked tube is one that has not been subjected to any process after manufacture other than simple cutting to length or smoothing of the ends, and has not been shaped into a specific tool or apparatus.
Which countries are the top exporters of fused silica tubes (HS 700231)?
In 2025, the top exporters of HS 700231 (the code used for fused silica tubes) in UN Comtrade data were the United States ($155M, 43% of world exports), Germany ($100M) and China ($40M). World exports came to about $363M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of fused silica tubes (HS 700231)?
In 2025, the top importers of HS 700231 (the code used for fused silica tubes) in UN Comtrade data were the United States ($97M, 19% of world imports), Mexico ($83M) and China ($62M). World imports came to about $504M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Is the HS code for Fused silica tubes the same in all countries?
The base HS code 700231 for Fused silica tubes is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for fused silica tubes in Brazil?
In Brazil, fused silica tubes (HS 700231) is classified under NCM 7002.31.00.