Feldspar

Overview

Feldspars make up about 60% of the Earth's crust. They are anhydrous aluminosilicate minerals in two main series: the potassium-to-sodium alkali feldspars and the sodium-to-calcium plagioclase feldspars.¹ The common end members, orthoclase (KAlSi₃O₈) and albite (NaAlSi₃O₈), both have a Mohs hardness of 6 to 6.5.²³

Commercially, feldspar is valued as a flux. Its potassium, sodium and calcium lower the melting temperature of glass and ceramic batches, and its alumina and calcium make glass more resistant to physical and chemical breakdown.¹

The EU added feldspar to its critical raw materials list in 2023 because its supply risk rose: EU import dependence increased and imports from Türkiye doubled, reaching 51% of EU needs.⁴ Feldspar is listed in Annex II of the Critical Raw Materials Act.⁵ It is not on the US 2025 List of Critical Minerals.⁶

Where it comes from

Feldspar is mined from pegmatites, granites and feldspathic sands. Resources are large, though not always conveniently located near the main centers of consumption.⁷

World production was an estimated 31 million t in 2025. India (6.0 million t), Türkiye (5.3 million t), Iran, China, Italy and Thailand together accounted for 74%.⁷ The EU itself is a significant producer: the 2023 EU study found that Italy, Spain, France, Czechia, Germany and other member states extract about 14% of global supply.⁴

• India6,000,000 t · 19%
• Türkiye5,300,000 t · 17%
• Iran3,900,000 t · 13%
• China3,700,000 t · 12%
• Italy2,200,000 t · 7%
• Thailand1,900,000 t · 6%
• Other countries8,100,000 t · 26%

World total shown is the sum of USGS country estimates; USGS rounds it to 31 million t. Other countries includes the United States, Brazil, South Korea, Morocco, Russia, Saudi Arabia and Spain. Source: Mineral Commodity Summaries 2026: Feldspar and Nepheline Syenite

In the United States, six companies mined feldspar at eight operations in North Carolina, California, Idaho and Virginia, producing an estimated 440,000 t in 2025. Two companies also produced nepheline syenite in Arkansas.⁷

China (730 million t) and Türkiye (720 million t) report the largest reserves; USGS describes world reserves as large.⁷

What it is used for

Glass and ceramics account for almost all feldspar use. In the United States in 2025, ceramics, pottery and miscellaneous uses took 53% and glass 47%, including fiberglass insulation, flat glass, containers and specialty glass.⁷

{{chart:end-uses}}

In glassmaking, feldspar's alkalis reduce melt viscosity and melting temperature and help quartz and other batch materials fuse. In ceramics, including tile, sanitaryware, tableware and electrical insulators, feldspar acts as a flux and controls how far the body vitrifies during firing. Smaller amounts are used as fillers and extenders in paint, plastics and rubber.¹ Calcium-rich plagioclase (anorthosite) can be used as an alumina source for glass fiber.¹

Demand therefore tracks construction and packaging. USGS links feldspar use to housing starts, through plate glass, ceramic tile, sanitaryware and insulation, and to a shift from plastic toward glass packaging.⁷

Grades and forms

Feldspar is sold by mineral type and by particle size. It is ground to about 20 mesh for glassmaking and to 200 mesh or finer for most ceramic and filler uses.⁷ Alkali feldspars are used mostly in glass and ceramics, while sodium-rich plagioclase goes mainly into ceramics. US production also includes feldspar-quartz mixtures from silica producers and aplite, a rock dominated by quartz and feldspar.¹

Trade and policy

The United States is largely self-sufficient in feldspar but imports most of its nepheline syenite. Net import reliance for feldspar was 18% in 2025, against more than 95% for nepheline syenite. In 2021–24, Türkiye supplied 93% of US feldspar imports and Canada 99% of nepheline syenite imports. Estimated feldspar imports fell by 35% in 2025. Both materials enter the United States duty-free under normal trade relations.⁷

The EU's 2023 assessment, based on earlier-year data, found that Türkiye was the largest global supplier of feldspar (32%) as well as the main source of EU supply (51%).⁴ More recent USGS estimates put India slightly ahead of Türkiye in 2025 world output.⁷ Feldspar is a critical, not a strategic, raw material under the Critical Raw Materials Act.⁵

This section is factual background, not legal or trade-compliance advice.

Recycling and substitution

Feldspar and nepheline syenite are not recycled by producers. However, glass container makers use cullet (recycled container glass), which reduces the amount of feldspar and nepheline syenite they need.⁷

Imported nepheline syenite is the main alternative to feldspar. In some uses, feldspar can also be replaced by clays, electric furnace slag, feldspar-silica mixtures, pyrophyllite, spodumene or talc.⁷

Sources

1. 2019 Minerals Yearbook: Feldspar and Nepheline Syenite (advance release). U.S. Geological Survey, accessed 2026-10-03. ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Handbook of Mineralogy: Orthoclase. Mineralogical Society of America, accessed 2026-10-03. ↩

3. Handbook of Mineralogy: Albite. Mineralogical Society of America, accessed 2026-10-03. ↩

4. Study on the Critical Raw Materials for the EU 2023 – Final Report. European Commission, DG GROW, accessed 2026-10-03. ↩ ↩² ↩³

5. Regulation (EU) 2024/1252 (Critical Raw Materials Act). EUR-Lex, accessed 2026-10-03. ↩ ↩²

6. Final 2025 List of Critical Minerals. Federal Register, accessed 2026-10-03. ↩

7. Mineral Commodity Summaries 2026: Feldspar and Nepheline Syenite. U.S. Geological Survey, accessed 2026-10-03. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹