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HSChapter 25
U.S. imports of mullite (HS 250860) totaled $1.6M in April 2026, traded with 7 countries.
Importers of Mullite paid $76K in duties in April 2026 — an effective duty rate of 20% on $387K in dutiable value, based on actual customs collections rather than the published tariff schedule. Mullite imports of $1.6M in April 2026 ran 59% above the year-to-date monthly average of $992K.
Last updated: April 2026 dataMullite is a high-performance aluminosilicate mineral prized in the refractory and advanced ceramics industries for its exceptional thermal stability, low thermal expansion, and resistance to creep at elevated temperatures. It serves as a critical raw material for kiln furniture, furnace linings, and technical ceramic components used in steel, glass, and aerospace manufacturing. The sole US tariff line for this mineral is 2508600000, making classification straightforward, though distinguishing natural from synthetic mullite can affect duty treatment and sourcing decisions.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
Mullite is classified specifically under HTS 2508600000 as a naturally occurring or synthetically produced aluminosilicate with a defined crystal structure. Customs may request mineralogical analysis or a certificate of composition to confirm the product meets the mullite specification rather than being classified as a generic clay or other mineral.
The primary demand comes from refractory manufacturers supplying the steel, glass, and ceramics industries, where mullite's high melting point and low thermal expansion make it essential for kiln furniture, furnace linings, and high-temperature structural components.
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Monthly import values over time
HS10 import codes under this HS6 parent. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Duty Collected |
|---|---|---|---|---|
| 2508600000 | MULLITE | $1.6M | 19.75% | $76K |
MULLITE
HS10 export codes under this HS6 parent. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 2508600000 | MULLITE | $971K |
MULLITE
1.5K t
PORTLAND CEMENT EXCEPT WHITE PORTLAND CEMENT
HS 252329
SULFUR OF ALL KINDS, NOT SUBLIMED,PRECIP,COLLOIDAL
HS 250300
SALT INCL TBL/DENTRD, PURE SODM CHLOR ETC; SEA WTR
HS 250100
UNGRND NAT CAL PHSPH, ALUM CAL PHOS A PHOS CHALK
HS 251010
FLUORSPAR OV 97% OF CALCIUM FLUORD BY WGHT
HS 252922
PEBBLES, GRAVEL ETC. FOR CONCRETE AGGREGATES ETC.
HS 251710
| Port | Imports | Exports | Balance |
|---|---|---|---|
| BUFFALO-NIAGARA FALLS, NY | $1.2M | $104K | -$1.1M |
| LAREDO, TX | -- | $694K | +$694K |
| NORFOLK-NEWPORT NEWS, VA | $128K | $15K | -$113K |