What Is Quartz Sand? Properties, Types and Applications
What is quartz sand, and what sets it apart from silica sand? We explain its high SiO₂ purity, its granular and micronised types, and applications such as glass, ceramics, engineered stone and paint.
Quartz sand is the fundamental raw material of industries that demand high purity — from the clarity of glass to the hardness of engineered stone, from the durability of paint to the whiteness of ceramics. It is often used interchangeably with silica sand, but quartz represents the higher rung of the purity scale. In this article we explain what quartz sand is, how it differs from silica sand, its granular and micronised types, and why it is preferred in particular industries.
What Is Quartz and How Does It Differ from Silica Sand?
Quartz, with the chemical formula SiO₂ (silicon dioxide), is one of the most abundant minerals in the Earth's crust. Thanks to its high resistance to mechanical and chemical weathering, it survives in nature without breaking down; this is also why most beach and desert sands consist largely of quartz.
So what is the difference between quartz sand and silica sand? Both are based on the same mineral — quartz; the difference lies in purity. "Silica sand" generally describes natural sand containing 95–99% SiO₂, while the term "quartz" usually implies higher purity (around 99–99.8% SiO₂) and a lower iron content. In other words, quartz sand is high-purity silica sand that has been largely freed of impurities, selected and processed. We cover this distinction in more detail in a separate article.
Properties of Quartz Sand
The properties that make quartz ideal for high-value applications are:
| Property | Value / Description |
|---|---|
| Chemical formula | SiO₂ |
| SiO₂ purity | typically up to 99.8% |
| Hardness | Mohs 7 |
| Density | ~2.65 g/cm³ |
| Melting point | ~1,700 °C |
| Iron content | very low |
| Colour / whiteness | high (low impurities) |
| Chemical stability | inert to acids and most chemicals |
High SiO₂ purity and low iron give quartz the whiteness and colour consistency that are critical in glass and ceramics. Its Mohs 7 hardness provides abrasion resistance in applications such as paint and engineered stone. Its high melting point and chemical stability make quartz indispensable in the refractory and chemical industries.
Granular Quartz and Micronised Quartz: The Grain Size Difference
Quartz is produced in different finenesses depending on the intended use, and the industry generally divides it into two main groups:
- Granular quartz: coarser-grained quartz in sand form. It is used in applications where grain structure and melting behaviour matter, such as glass, refractories, metallurgy, sodium silicate and engineered stone.
- Micronised quartz: quartz ground into a micron-sized powder. It is preferred in applications requiring fine particles, such as paint, adhesives, composites and electronic fillers.
As a general distinction, products coarser than a certain fineness (about 120 mesh) are referred to as "quartz sand", while more finely ground products are called "quartz powder". The fineness of micronised quartz is usually expressed in microns (µm), and the application determines the required average particle size.
Where Is Quartz Used?
Compared with silica sand, quartz applications are concentrated in sectors with greater purity and colour sensitivity:
- Glass industry: the main raw material of glass; high SiO₂ and low iron are essential for clear glass. Glass industry →
- Ceramics and porcelain: provides dimensional stability, whiteness and strength in bodies and glazes. Ceramics → · Porcelain →
- Engineered stone (artificial marble): makes up most of the product by weight, providing hardness and aesthetics. Engineered stone →
- Paint and coating fillers: micronised quartz adds abrasion resistance, hardness and chemical durability to paint. Paint industry →
- Chemical industry and sodium silicate: the basic raw material of silicon-based chemicals and water glass. Chemical industry →
- Refractories and metallurgy: used for high-temperature resistance and as a slag former. Refractories → · Metallurgy →
- Electronic fillers: for thermal stability and insulation in epoxy encapsulation and casting resins. Electronics →
You can browse all quartz applications here.
Why Are Purity and Iron Critical in Quartz?
The single most important parameter determining quartz quality is usually its iron (Fe₂O₃) content. Iron creates colour, particularly in glass; the iron limit for clear (flint) glass is therefore very low, while higher values are acceptable in container and coloured glass. In paint and filler applications, low iron means high whiteness and affects the colour of the final product. In glass, elements such as aluminium, magnesium, calcium and potassium also alter melting behaviour, while titanium and chromium can add colour to the glass. Quartz is therefore assessed not only by its SiO₂ content but by its full chemical composition, depending on the application. We cover the role of iron in glass production in more detail in a separate article.
Conclusion
Thanks to its high SiO₂ purity, low iron and hardness, quartz sand is the backbone of purity-demanding industries such as glass, ceramics, engineered stone, paint and chemicals. The key to choosing the right product is defining precisely the purity, iron limit and grain size (granular or micronised) that your application requires. To determine the right quartz for your application, please get in touch with us.