Potash, Phosphate, Quartz and Industrial Minerals

What counts as an industrial mineral

Industrial minerals are mined for their physical or chemical properties rather than for a metal extracted from them. Potash and phosphate feed crops, quartz sand becomes glass and silicon, feldspar goes into ceramics, bentonite clay into drilling mud and cat litter, and talc, kaolin and calcium carbonate into paper, paint and plastics. They rarely make headlines, but by tonnage they are a large part of world mining.

Because the products are sold to a specification, the questions for a deposit are different from those for gold or copper. Purity, particle size, color and how close the deposit is to its buyers often matter as much as the size of the resource.

Potash

Potash is the general name for potassium-bearing salts, most of all potassium chloride, sold as muriate of potash (MOP), the world’s main potassium fertilizer. It comes from evaporite beds left behind when ancient seas dried out, often hundreds of meters underground.

According to the USGS Mineral Commodity Summaries 2025, Canada was the largest potash producer and the leading exporter in 2024, with Russia, Belarus and China among the other large producers. Canada’s mines are concentrated in Saskatchewan, where potash is mined either by conventional underground methods or by solution mining, which dissolves the salts with hot water pumped down wells and recovers potash from the brine at the surface. Our guide to potash mining in Canada covers where the mines are, and the piece on potash exporting countries looks at trade.

Phosphate rock

Phosphate rock supplies the phosphorus in fertilizers such as DAP, MAP and superphosphate, and smaller amounts go into animal feed, food additives and, increasingly, lithium iron phosphate batteries. Most of it comes from marine sedimentary deposits mined in large open pits, with some from igneous deposits.

The USGS phosphate rock summary lists China, Morocco, the United States and Russia as the leading producers in 2024, in that order, and Morocco and Western Sahara as holding by far the largest reserves. Processing usually means treating the rock with sulfuric acid to make phosphoric acid, which leaves a by-product called phosphogypsum that has to be stored and managed. Our explainer on the phosphate mining process walks through the steps.

Quartz, feldspar and mica

Quartz is the most common mineral in the continental crust, so its value depends almost entirely on purity and form. Ordinary silica sand goes into glass, foundry molds and construction. High-purity quartz, with very low levels of iron, aluminum and other impurities, is needed for semiconductor crucibles and solar-grade silicon; the Spruce Pine district in North Carolina is the best-known source. Large clear crystals are collected as specimens, and quartz veins are where prospectors often find gold and sulfides such as pyrite and galena.

Feldspar and mica often occur with quartz in granites and pegmatites. Feldspar supplies alumina and alkalis for glass and ceramics. Mica, including muscovite and biotite, splits into thin heat-resistant sheets used in electrical insulation and is ground for paints and coatings. Our guides to the types of quartz rock and their uses and to feldspar, quartz and mica go into each mineral.

Bentonite and other clays

Bentonite is a clay made mostly of smectite minerals such as montmorillonite, usually formed from altered volcanic ash. Sodium bentonite swells many times its dry volume when wet, which makes it useful for drilling mud, sealing ponds and landfill liners, binding foundry sand and making clumping cat litter; Wyoming is the classic source. Calcium bentonite swells less and is used more as an absorbent and in animal feed. Kaolin, a white clay, is used to coat paper and in ceramics and paint. With clays, the lab tests on swelling, brightness and absorbency decide the market a deposit can sell into.

How industrial mineral deposits are judged

An industrial mineral deposit is worth developing only if it can meet a buyer’s specification at a delivered cost that competes with other sources. That puts weight on factors a metal explorer might treat as secondary:

Exploration still starts with finding where the right rock is. Our satellite mineral detection service has been used on industrial minerals as well as metals, including bentonite, ranking Exploration Targets from multispectral, shortwave-infrared, radar and terrain data. It works ahead of sampling, test work and any JORC or NI 43-101 estimate, and never replaces them.