What is so great about Granite?

Often we take for granted the accessories and products that nature helps supply. Whether it be a wooden bowl made from British Oak, a stainless steel cutlery set deriving from the initial fusion of steel and chromium or even the clothes we wear; coming from natural living organisms such as sheep’s’ wool or cotton from Gossypium plants.

However, kitchen worktops made from granite has a long time process, with the first step in the production line starting over 50 million years ago.

In today’s society, a person’s first conscious thought when consuming a product is price, and it is nearly always the case of never recalling the origin of the product and its overall supply.

Granite is an intrusive and felsic rock; a rock with medium to coarse texture, occasionally with some individual crystals larger than the groundmass forming a rock known as porphyry. Granites can be pink to dark gray or even black, depending on their chemistry and mineralogy. Outcrops of granite tend to form tors, and rounded massifs. Granites often occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels.

Granite is an igneous rock and is formed from magma. Granitic magma has many potential origins but it must intrude other rocks. Most granite intrusions are emplaced at depth within the crust, usually greater than 1.5 kilometres and up to 50 km depth within thick continental crust. The origin of granite is contentious and has led to a variety of classifications. Classification schemes are regional; there is a French scheme, a British scheme and an American scheme. This confusion arises because the classification schemes define granite by different means. Generally the 'alphabet-soup' classification is used because it classifies based on genesis or origin of the magma.

Granitoids are a ubiquitous component of the crust. They have crystallized from magmas that have compositions at or near a eutectic point (or a temperature minimum on a cotectic curve). Magmas will evolve to the eutectic because of igneous differentiation, or because they represent low degrees of partial melting. Fractional crystallisation serves to reduce a melt in iron, magnesium, titanium, calcium and sodium, and enrich the melt in potassium and silicon - alkali feldspar (rich in potassium) and quartz (SiO2), are two of the defining constituents of granite.


This process operates regardless of the origin of the parental magma to the granite, and regardless of its chemistry. However, the composition and origin of the magma which differentiates into granite, leaves certain geochemical and mineralogical evidence as to what the granite's parental rock was. The final mineralogy, texture and chemical composition of granite is often distinctive as to its origin. For instance, granite which is formed from melted sediments may have more alkali feldspar, whereas granite derived from melted basalt may be richer in plagioclase feldspar. It is on this basis that the modern "alphabet" classification schemes are based.

Nowadays fracture propagation is the mechanism preferred by many geologists as it largely eliminates the major problems of moving a huge mass of magma through cold brittle crust. Magma rises instead in small channels along self-propagating dykes which form along new or pre-existing fault systems and networks of active shear zones. As these narrow conduits open, the first magma to enter solidifies and provides a form of insulation for later magma.

Granitic magma must make room for itself or be intruded into other rocks in order to form an intrusion, and several mechanisms have been proposed to explain how large batholiths have been emplaced:
• Stoping, where the granite cracks the wall rocks and pushes upwards as it removes blocks of the overlying crust
• Assimilation, where the granite melts its way up into the crust and removes overlying material in this way
• Inflation, where the granite body inflates under pressure and is injected into position

No matter of the classification scheme, it is the case that granite is a special resource and encounters the most intrinsic paths of development. And from being formed, to then mined and quarried, to being cut into shape and fitted into a kitchen worktop, granite has taken a long path, and one that must be appreciated, thus enhancing the feel of the history of the stone and what it brings to you kitchen.

Granite Worktops UK

This is the first blog of the blogspot! Rock Revelations supply top quality granite kitchens to Uk home developers. There are plans ahead to create a new user friendly website, and move into a new era.

Rob Stewart
Granite and Silestone Kitchen Worktops