Stone Countertops at AllGraniteAndMarbleFilms.com
Natural Stone Countertops

• Stone Counertops - Slate history
• Slate – Stone countertops

Slate – Stone countertops

Kind of rock: clastic stone coming from the sedimentation of a very thin mire that follows a double process: cementation and lamination. Composition in percentage: SiO2 22-46%; Al2O3 2-18%; CaO 20-39%; FeO 1-10% Specific gravity: 2600-2900 Kg/ml Compression: some compression trials on dry and wet test-tubes done both parallel and perpendicular to the veins have shown resistances with a minimum of 900 Kg/cm and a maximum of about 1600 Kg/cm, taking into consideration the extreme values in different situations. Even after the experiments of cooling its resistance is excellent.

Countertops age - Slate is of differing ages depending on its location: For example Welsh Slate used in the building industry: Penrhyn Slate 560-530 million years old (Cambrian) Festiniog Slate 480-500 million years old (Ordovician) Aberllefeni Slate 450-480 million years old (Ordovician

The colour and composition of stone countertops vary depending on the mineral content of the original rock - and these all depend on what type of rock was being eroded on land at the time. Carbon makes the slate dark grey Mica more mica helps the slate split into thinner sections (Mica is a sheet-like crystal that looks a bit like flaky paint when you see it in its pure form.) Chlorite a type of mica gives slate a dark greeny colour Quartz more quartz (sand) makes the slate stronger and it polishes better Iron oxide (haematite) - in Cambrian slate gives a red/purple hue to the rock. The haematite coats the grains of the mud, masking the green colour of the chlorite. I hope this is of some help in choosing countertop.