Curly Red Haired Girl At The Brick Wall

Calcium silicate bricks
The raw materials for calcium silicate bricks include lime mixed with quartz, crushed flint or crushed siliceous rock together with mineral colourants. The materials are mixed and left until the lime is completely hydrated, the mixture is then pressed into moulds and cured in an autoclave for two or three hours to speed the chemical hardening. The finished bricks are very accurate and uniform, although the sharp arrises need careful handling to avoid damage to brick (and brick-layer). The bricks can be made in a variety of colours, white is common but pastel shades can be achieved.
It is very common in Sweden, especially in houses built or renovated in the '70s. It is referred to as "Mexitegel" (en: Mexican Bricks).
In India these are known as Fly ash bricks, manufactured using the Falg process.