7 min read · Updated 23 July 2026

Silica Sand Specifications Buyers Should Check (SiO₂, Fe₂O₃, PSD, pH, LOI)

Before buying silica sand, check five specifications: SiO₂ purity (how much is silica), Fe₂O₃ (iron oxide content), particle size distribution or PSD (grain size range), pH and moisture, and loss on ignition (LOI). The right values depend on your application — glass needs very low iron, foundries need a target grain fineness, filtration needs a controlled size range.

SiO₂ purity

This is the percentage of the sand that is silicon dioxide. Higher purity means fewer contaminants. Glass and high-end industrial uses need 99%+; construction is less demanding.

Iron content (Fe₂O₃)

Iron oxide tints glass green or brown and can interfere with some processes. Glass grade sand keeps Fe₂O₃ below 0.02%. Always ask for the iron figure, not just the SiO₂ number.

Particle size distribution (PSD)

PSD describes the spread of grain sizes, usually as a sieve analysis or a mesh range. Filtration, foundry and frac applications each need a specific, consistent PSD. Ask for the sieve analysis.

pH, moisture and loss on ignition (LOI)

pH and moisture affect handling and downstream chemistry. LOI measures the material burnt off at high temperature (organics, carbonates) and matters for foundry and glass. Request these on the test report.

  • Ask for a recent laboratory test report, not just a datasheet.
  • Confirm the values are typical batch results, and whether they are guaranteed.
  • State your own target spec so the supplier can confirm they can meet it.

Frequently Asked Questions

What SiO₂ purity should I ask for?

It depends on use: 99.5%+ for glass, 99%+ for demanding industrial uses, and standard washed grade for construction.

Why does iron content matter in silica sand?

Iron oxide (Fe₂O₃) colours glass and affects some chemical and foundry processes, so low-iron sand is needed for clear glass and sensitive applications.

What is loss on ignition (LOI)?

LOI is the mass lost when the sand is heated strongly, indicating organics or carbonates. It is important for foundry and glass grades.