# silica

/ˈsɪɫəkə/ (US) · /sˈɪlɪkɐ/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/silica
Updated: 2026-05-07

## Definition

a hard, white or colorless mineral found in sand, quartz, and glass. It is one of the most common materials on Earth and is used to make things like computer chips and concrete.

For teachers: a hard, unreactive, colorless compound occurring as the mineral quartz and as a principal constituent of sandstone and other rocks. Chemically known as silicon dioxide (SiO2), it is a fundamental component in the manufacture of glass and ceramics.

## Examples

- Sand is mostly made of silica.
- Construction workers must wear masks to avoid breathing in fine silica dust while cutting stone or concrete.
- The high silica content in the volcanic ash resulted in a particularly viscous lava flow that moved slowly across the valley floor.

## Usage notes

- Uncountable when referring to the chemical compound; occasionally countable in geological contexts when referring to different types of the mineral.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.