silica
/ˈsɪlɪkə
/noun [mass noun]
A hard, unreactive, colourless compound which occurs as the mineral quartz and as a principal constituent of sandstone and other rocks.
- Alternative name: silicon dioxide; chemical formula: SiO2.
- Quartz and sand are composed of silicon and oxygen alone: silicon dioxide, or silica.
- Cristobalite is a crystalline form of silica that has a diamondlike structure.
Derivatives
siliceous
- Quartz is the dominant mineral in veins in siliceous rocks, calcite in limestones, and gypsum in gypsiferous sediments.
- After initial fieldwork in 2000 we realized that the ‘upper siliceous zone’ can be further subdivided into two distinct siliceous horizons.
- Tectonic ironstone encompasses siliceous and ferruginous rock types that are characterized by the presence of chert or cherty quartzite, iron sulphides and their alteration products.
Origin
Early 19th century: from Latin silex, silic- 'flint', on the pattern of words such as alumina.
Rhymes
- at all events
- a tall order
- at all points
- a tall story (or tale)
- at a loss
- at a low ebb
- ataman
- AT & T
- at an angle
- at anchor
- AT and T
- a tangled web
- at any price
- at any rate
- at a (or one) stroke
- at a (or the) minimum
- atap
- at a premium
- at a price
- at a profit
- at a push
- ataractic
- at a range of
- at a rate of knots
- ataraxia