silica

American  

[sil-i-kuh] / ˈsɪl ɪ kə /

noun

1. the dioxide form of silicon, SiO 2 , occurring especially as quartz sand, flint, and agate: used usually in the form of its prepared white powder chiefly in the manufacture of glass, water glass, ceramics, and abrasives.

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silica British  

/ ˈsɪlɪkə /

noun

1. the dioxide of silicon, occurring naturally as quartz, cristobalite, and tridymite. It is a refractory insoluble material used in the manufacture of glass, ceramics, and abrasives

2. short for silica glass

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silica Scientific  

/ sĭl′ĭ-kə /

1. A chemical compound that is the main constituent of most of the Earth's rocks. Silica occurs naturally in five crystalline forms (quartz, tridymite, cristobalite, coesite, and stishovite), in a cryptocrystalline form (chalcedony), and in an amorphous form (opal). It is also the main chemical compound in sand. Silica is used to make glass, concrete, and other materials. Also called silicon dioxide. Chemical formula: SiO ₂ .

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Etymology

Origin of silica

1795–1805; < New Latin, derivative of Latin silex silex

Compare meaning

How does silica compare to similar and commonly confused words? Explore the most common comparisons:

• silica vs. silicon

Example Sentences

Avcoat is a mix of silica fibers, phenolic microballoons, and epoxy resin that chars and erodes, removing heat away.

From Barron's • Apr. 10, 2026

Workers at the Evonik plant were dispatched to close the gas supply valve into the factory, where the German chemical maker produces silica for toothpaste and food products.

From The Wall Street Journal • Feb. 10, 2026

In samples from Murray Springs, Blackwater Draw, and Arlington Canyon, the team found quartz grains marked by distinctive fractures, some of which were filled with melted silica.

From Science Daily • Jan. 1, 2026

A further, lesser known risk is that of silicosis, a lung disease caused by breathing in silica dust, usually over many years.

From BBC • Apr. 24, 2025

The scabs look like rocks, bumpy, with a sheen like silica; or else like some kind of fungus.

From "Cat's Eye" by Margaret Atwood