A mineral is a naturally formed, inorganic solid with a fixed chemical composition and an ordered crystal structure. Rock is a mixture of minerals: granite, for example, consists of feldspar, quartz and mica. In construction the word matters most as the opposite of organic — a mineral building material is stone-like and contains no wood, plastic or other carbon compounds.
Mineral building materials
Most of the structural and finishing materials in a house are mineral in origin:
- Quartz (SiO₂) — the main component of building sand and of many sandstones; hard and chemically very stable
- Calcite (CaCO₃) — the mineral of limestone and marble, and the raw material for lime and cement
- Gypsum (calcium sulphate) — the raw material for plasterboard, gypsum plaster and anhydrite screeds
- Clay minerals — the raw material for bricks and roof tiles
- Feldspar and mica — components of granite and of much ceramic ware
Application
The mineral origin determines how the material behaves, and therefore how you should treat it:
- Non-combustible. Purely mineral products such as mineral wool, calcium silicate block and concrete do not burn. That is why they are used where fire performance counts: around fireplaces, in fire walls and as insulation in escape routes
- Acid sensitivity. Calcite-based materials (marble, limestone, lime mortar) are attacked by acid. Never use vinegar, descaler or acidic façade cleaner on them; on quartz-rich stone such as granite this is far less of a problem
- Moisture sensitivity. Gypsum slowly dissolves in water and does not belong in permanently wet or external situations; use cement-bound products there
- Hardness. Mineral hardness is expressed on the Mohs scale, from talc (1) to diamond (10). Quartz sits at 7 and is harder than ordinary steel — which is why quartz-rich stone needs diamond tooling
- Vapour transport. Mineral finishes such as lime plaster and mineral paint are highly vapour-open, which is an advantage on damp, old masonry
Related terms
- Natural stone
- Limestone
- Granite
- Marble
- Gypsum
- Cement
- Mineral wool
- Brick
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.