What does siliceous mean?
Siliceous is a technical adjective meaning that something contains a substantial amount of silica, the compound of silicon and oxygen that occurs abundantly in quartz, flint, sand, glass, and many mineral deposits. The term is especially common in geology and paleontology, where it describes silica-rich rocks, sediments, and the hard structures or remains produced by microscopic organisms. A siliceous deposit might consist largely of the remains of tiny marine creatures whose skeletons were made from silica. The word can also convey a hard, flintlike character when applied to materials. Although understandable in ordinary contexts, it belongs mainly to scientific and specialist writing; “silica-rich” is usually the clearer choice for a general audience. Siliceous is related to silica, silicate, and silicic, all of which ultimately derive from the Latin word for flint or hard stone.
adjectiveContaining or consisting largely of silica, especially silica in the form of quartz or flint. In geology, the term describes rocks, minerals, sediments, or organisms whose composition or structure includes substantial silica.
- Containing or consisting substantially of silica.
- Hard or flinty in character, especially as a description of a rock or material.
"The siliceous remains of microscopic organisms accumulated on the seafloor and eventually formed dense deposits of silica."
"Geologists identified the pale, siliceous layers as deposits formed from the remains of tiny marine organisms."
"The specimen is predominantly siliceous, with traces of iron-bearing minerals visible along its fractured surface."
Siliceous means “full of silica,” a description that links microscopic skeletons, volcanic glass, flint, and some of the planet’s oldest rocks.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does siliceous come from?
Siliceous derives from Latin siliceus, meaning “made of flint” or “flinty,” which was formed from silex, a Latin word for flint or hard stone. English borrowed the adjective in the 17th century for descriptions of mineral and geological substances. Its relatives include silica, silicic, silicate, and silicify, all sharing the same ancient Roman source concerning flint or silica-bearing stone.
Related word forms
How siliceous is actually used
This is chiefly a formal scientific term used in geology, mineralogy, paleontology, and materials science. It is more technical than “silica-rich” and is not normally used in general descriptions of sand or soil.
Easily confused with siliceous
Siliceous describes a material containing silica, whereas silicic relates to silica or silicic acid and commonly occurs in terms such as silicic acid.