Natural stone is the collective name for hundreds of different types of stone. These are found and quarried all around the world. The characteristics and appearance of natural stone are determined by the way in which the stone was formed, often over millions of years. The main types of stone or rock are igneous, sedimentary or metamorphic.
No two places on earth will have experienced exactly the same geological history therefore each natural stone is unique. It also means that even natural stone of the same type can differ widely and some are better quality than others. It is important when buying natural stone to ensure it is the best quality you can afford, cheaper versions could give you problems.
For commercial purposes, natural stone is divided into large groups:
Granite
Marble
Limestone
Basalt
Slate
Sandstone
Granite
The word "granite" comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a holocrystalline rock. By definition, granite is an igneous rock with at least 20% quartz and up to 65% alkali feldspar by volume. The large group of the granites consists of igneous or magmatic rocks which were formed by the cooling of magma deep in the earth's crust.
Their outward appearance is usually dappled. Some granites are also metamorphic in origin, having been created by the transformation of existing igneous rock under high pressure (for example, during the development of mountain ranges when due to plate tectonics one layer of rock is forced under or above another pushing the top layer upwards bending and twisting it).
Granite is granular and phaneritic in texture. Granites can be predominantly white, pink, brown, black, green or grey in colour, depending on their mineralogy and are very hard.
It is also important to note that granite is a very porous rock and easily ‘sucks’ up contaminants from beneath drawing them to the surface of the rock. This is particularly important to know
Marble
Marble is a non-foliated metamorphic rock of recrystallized carbonate minerals, most commonly calcite or dolomite. Geologists use the term "marble" to refer to metamorphosed limestone. Marble contains both metamorphic and sedimentary rocks, all of which are composed of calciferous particles (calcite).
Marble is a relatively homogenous and compact natural stone. Because it is relatively easy to work, but also because of its wide variety of different colours (red, white, green, pink, yellow, black etc.), it has found many applications in the building industry: floors, staircases, fireplaces, etc.
Marble is a porous rock and easily stained therefore it is recommended that it is sealed before using it.
Limestone
Limestones are sedimentary rocks created by the accumulation and compression of fossils and/or stone fragments, such as quartz and calcium.
Limestone, that consists mainly of calcium carbonate, was formed on the bottom of shallow lakes and seas, deposited as loose particles of shells or formed chemically by the action of acidic water containing carbon dioxide. This slightly dissolves the calcium carbonate that is already present, which then reforms by binding onto particles of sand or shell. Over time these beds build up, are duplicated, and become further compacted by the weight and pressure caused by movement of the earth’s crust. Minerals, often oxides of iron, help to decide the various colours of stone available in all shades of white,
black, grey, buff and yellow.
The majority of limestones cannot be polished and are delivered with a lightly honed finish. The best known examples are the French white limestones, but other high quality types are available from Portugal, Turkey, etc. Travertine is a form of limestone deposited by mineral springs, especially hot springs. It is a hard but holey material, it usually comes in whites, creams and tan.
Basalt
Basalt is an igneous rock, created by the cooling of liquid magma on the earth's surface. Because this cooling was relatively rapid, the minerals in the stone had little time to complete the crystallisation process resulting in a fine-grained appearance. In general, basalts are non-porous, hard and capable of finishing in several different manners. Basalt is usually dark in colour.
Slate
Slate is a fine-grained metamorphic rock formed when sedimentary rock, typically shale, is subjected to great pressure.
Slate can be split into thin layers.
Slates have a highly layered structure, which gives the surface a 'split' appearance. A lightly honed finishing is possible as well, making the slates suitable for indoor and outdoor flooring and wall covering. Most slate comes in shades of grey. Some slate contains high levels of iron oxide and will ‘bleed’ red rust from the stone when it gets wet. When used as paving this bleeding can look very unsightly and normally is worse with cheaper imported stone from China. Depending on how deep the slate has been mined will also effect the strength and durability of the paving.
Sandstone
Sandstone differs because it is predominantly made up of particles of quartz that have been eroded from other rocks, often granite. These are carried away down streams and rivers until they are eventually deposited. Occasionally they are formed by winds carrying them, like the shifting sands of a desert. Natural cement minerals occur in the groundwater and help to glue the particles together. As with limestone, time and the weight of other material on top compacts the sand to form stone.
Sandstone is a classic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Sandstone can be any colour, but the most common are: tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colours of sandstone have been strongly identified with
certain regions.
Care & Maintenance:
What care and maintenance of the stone products are recommended?
Stone surfaces are very easy to maintain is you use the right products. Never use acid cleaners or abrasive chemicals on stone. Take a look at our EASYCare range of cleaners, we ensure they are as environmentally friendly as possible whilst still getting the job done! We suggest you also consider sealing sensitive stone. Note: If jointing your paving with EASYJoint, seal the paving before using EASYJoint or wait for 4 weeks after it has been done to ensure optimum performance of the products.
How often do I need to apply an EASY Sealer to my natural stone surfaces?
There is no set rule on how often to seal your natural stone. Sealing can be as frequent as six months for higher traffic areas to every couple of years. Using a quality sealer with a higher scrub rate will last longer.
Why does granite need to be sealed?
All natural stone including marble and granite, can be sealed to protect against staining. Granite will absorb substances from above and below leaving unsightly stains and marks therefore it is important to seal all sides of the stone.
What can I use to seal natural stone and tile and where can I buy it?
A sealer that penetrates and protects natural stone whilst allowing it to breath is essential. Do not be tempted to seal stone with a sealer that puts a ‘skin’ over it. EASYSeal products for natural stone are water based and do allow the stone to breath whilst giving maximum protection against staining. Click on the ‘finding a stockist’ link and it will give you information on how to find your nearest stockist or ask for an EASYSeal product from your nearest hardware store.
What can I use to clean travertine, marble, or granite paving?
Neutral cleaners are needed to clean natural stone tiles. Acidic or alkaline cleaners should be avoided as they can open the pores of the natural stone and change the colour of the surface. EASYCare sealers are designed not to damage natural stone whilst cleaning to the highest standards.
How can I enhance the colour of travertine or other types of natural stone?
Enhancing the appearance of natural stone is easily achieved by using EASY Colour enhancer. It also seals the paving giving excellent protection against staining. If using Slate or Limestone use EASY Slate & Limestone Sealer, a bespoke sealer designed specifically to enhance and seal these types of stone.
Do I need to seal porcelain tiles?
Porcelain tile does not need to be sealed. However if using EASYJoint ensure the ground below and the bedding mix is permeable with a strength no greater than 6:1
A large quarry