silica
n. uncountablen. 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.
n. 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.
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.
From New Latin silica, from Latin silex (“hard stone, flint”), on model of alumina, soda.
Uncountable when referring to the chemical compound; occasionally countable in geological contexts when referring to different types of the mineral.