Zillions of Little Tiny Shells

Limestone is a sedimentary soft rock that consists of mainly calcium carbonate. In its pure state it is white, but it may be colored by other materials. Limestone is formed either from accumulation of animal shells in a calcium carbonate cementing matrix or by crystallization from solution.

All limestone is highly porous – a tablespoon of water on a limestone surface will be absorbed in seconds, although it does vary in porosity from piece to piece. Porosity is also affected by its finish – highly polished limestone is a little harder to penetrate than limestone with a honed (matte) finish.

Due to its high porosity it is particularly important for limestone to be sealed with a high quality impregnating sealer which will not affect its slip resistance or look. Limestone is used both outdoors and indoors, and Total Seal’s premium impregnating sealers will seal limestone equally well in both.

It is very difficult to seal limestone against acid attack.

Limestone and other calcite based stone such as marble and travertine are prone to acid etching. Limestone is immediately ‘etched’ (eaten/corroded) by any acidic material on contact – including lemon juice, cola, wine and champagne.

For this reason the honed (matte) look is popular, as it doesn’t show the matte etch marks as much as polished limestone. In any case, acidic substances should be cleaned up as soon as possible, and limestone should not be used outdoors in areas where there is acid rain.