The Stone Dictionary
Our experts give you insider's knowledge
At RMS, we have years of industry experience. Here, you’ll find some background on all the main types of natural stone that we have on offer for you.
Basalt is one of the most abundant rock types in the world. It’s usually grey to black in colour and fine-grained and can be characterised by small holes in the stone structure formed as the lava rapidly cooled on the earth’s surface. Basalt’s grey tones and subtle patterns make Basalt a popular choice for interior designs as well as outdoor uses. Basalt is hardwearing and classic, often being used for countertops, flooring and wall cladding and is usually produced in a sawn or honed finish in both filled and unfilled textures.
Travertine is a sedimentary rock formed similarly to limestone. The main difference between the two is that during its formation, hot mineral spring water has filtered through the stone causing holes and voids. Because of this, travertine is very distinctive and gives a unique look every time. Travertine tiles come in two kinds of cut; vein cut or crosscut. You do have the option of filling the tiles and gives a much smoother surface to the stone. But be aware that during usage and over time small areas the fill may become loose. This is normal and can easily be refilled with the correct grout or resin.
Granite is a hard, crystalline, igneous rock formed from molten magma that has cooled way down below the earth’s surface. Granite is one of the hardest stones you can get, making it great for highly used surfaces such as kitchen benches. Pro tip: Granite contains a diverse array of mineral crystals, some of which may be sensitive to acid— so it is essential to ensure that the correct sealers and cleaners are used.
Sand is the most common material on the earth’s surface, so it’s not surprising that sandstone is a popular choice. Sand contains quartz and feldspar, and when it’s compressed, it creates this well-known stone. Our sandstone tiles and pavers come in honed or natural split finishes. A honed finish will give you a smooth finish, while a natural split will provide you with a rough finish.
A limestone is a form of sedimentary rock composed of a mixture of seashell, sand, and other types of organic matter. Every type of limestone in our product range has its own distinctive colours and markings and can occasionally differ notably in density. Some kinds of limestone look like marble, as limestone is an earlier developed version of marble. As with most natural stones, some amount of edge chipping can occur as well as surface pitting. There can also be amounts of fossilised shells, striations, and some resin filling. All these natural characteristics make stone unique. Pro tip: limestone is sensitive to products containing acid so care should be taken when choosing sealing and cleaning products.
Years and years ago, the name marble was a term given to any stone that had a polished finish. In reality, marble is derived from limestone that has gone through further processes in the earth like the addition of minerals and being exposed to higher temperatures. A lot of marble is found where there has been a lot of old volcanic activity, and these processes lead to a stone that has a solid closed surface with some slight open veining giving the stunning trademark look. Marble has been used in buildings for thousands of years because of its plethora of beautiful shades and veining, and it comes both in a polished and tumbled finish.
Slate is one of the finest rocks, known for its durability and weather resistance. Slate is easily split into smooth, flat plates and tiles come in a calibrated or uncalibrated state. Un-calibrated tiles require sorting before laying, generally thicker tiles are laid first as you can always raise thinner tiles with more adhesive. Slate can be used internally or externally making it a versatile option.
These are dense, metamorphic rocks that offer considerable shade variation, ranging from light cream/white to charcoal grey/black with many colours in between. They often contain reflective crystals which glisten in the light, adding something special to any surface. Highly textured split face panels are available in both Schist and Quartzite.
Porphyry is a hard-wearing and durable igneous (volcanic) rock often used to pave driveways and outdoor areas. Porphyry can be sourced in a myriad of colours from reds and browns, to blues, greens and fawns. The rock also features large crystals of quartz or feldspar, and have excellent non-slip characteristics.
Porcelain tiles are ceramic tiles with low absorbency they are made from clays fired at high temperatures to increase the density and durability of the tile. Porcelain tiles have little variation within a single production run but sometimes size can vary slightly. So it is best to buy all your porcelain tiles at the same time to avoid any size variation.
