How Limestone is formed

What is Limestone?

Limestone is a sedimentary rock, which means it was formed from the pile up of small rock particles that have been gathered by pressure. Coral, oysters, shell, algae, mussels and some other organisms living in the ocean use calcium carbonate (CaCO3) found in seawater to produce their bones and shells. Whenever these organisms die, their shell and skeletal debris accumulate as sediment on the ocean floor where they are gathered for millions of years, forming limestone from the sediments and the pressure of the ocean water.

Portland stone

Portland Stone is a limestone that is very popular as a building material across the globe, particularly where outstanding architectural effect is desired. With rich heritage, simple and clean beauty, Portland stone has remarkably been used in building residential homes, staircases, as well as important political and financial buildings. Portland stone has a subtly unique texture, grain and color.

Types of Portland stone

Two of the several variants of Portland stone include: Basebed and the Whitbed.

  • The basebed is the oldest and the most pure of color and grain, gotten from the bottom layers of Portland Stone when quarried. It is ideal for flooring, stairs, ashlars walls and complex stonework.
  • The whitbed on its own is a very durable Portland stone type with a distinctive fossil structure. It is slightly more textured with variation in color. It is perfect for paving, cladding and stairs.

Even though the two bed stones have different unique qualities, there are still some features they share in common. For instance, they are all off-white to light grey, notably uniform in color but with tiny dark specks.

Looking to install exceptional steps in your house? Portland Stone, with its subtle hues and calm palette is the perfect material for the job. It is extremely adaptable and matches the interior design as well as the general aesthetic of any place it is installed. Apart from having a neutral coloring, its completed texture can range from remarkably smooth to uniformly mottle.

PORTLAND STONE STEPS is a natural stone step specialist. Whether it is basebed Portland stones or whitbet Portland stones, they can supply and install stone steps anywhere in London. For more details on getting Portland stones, choosing a stone type or to get a free no-obligation supply quote, contact PORTLAND STONE STEPS on 07950 404 610 or visit

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