Each month we share ideas for the ways natural stones can be used to enhance your home. We know that they are durable, easy to clean and look after, and they look beautiful. But what actually are these stones, where do they come from and how do they end up in our homes? We explore a little bit about two of the most popular stones used in homes and businesses around the world; granite and marble.
GRANITE
Granite is an igneous rock, a type of rock formed when magma slowly solidifies and crystallises below the Earth’s surface. When we look at granite we can see large crystallised grains. Granite is predominately composed of quartz and feldspar, but other minerals including mica and amphiboles are present as well, and it’s this mixture of minerals that gives each piece of granite it’s unique colour. Many are black, grey, white, pink and gold.
It is the most common igneous rock on Earth and therefore we’re likely to encounter it in everyday life, as paving stones, cladding for buildings, curbing, staircases, gravestones, and of course kitchen worktops. Granite is found all over the world but India and Brazil are two of the biggest exporters of granite. India has such an abundance they only quarry 3% of the granite that they have. It’s found close to the surface so quarries are shallow, and are predominately quarrying granite that’s above ground. Small holes are drilled into the granite and a small explosive separates it from the surface. Once cut in to blocks and then slabs, it’s shipped all over the world to stone stockists. From there it’s bought by local stone masons who cut and finish the stone for their customers.
MARBLE
Marble is a metamorphic rock formed when limestone (a sedimentary rock) is subjected to heat and pressure – metamorphism. It’s composed of many minerals, primarily calcite, as well as clay minerals, micas, quartz, iron oxides and graphite. Under the conditions of metamorphism, a mineral called calcite, found in limestone, recrystallizes to form a rock with interlocking crystals, you can see this when you look at a piece of cut marble.
Marble is typically much lighter in colour than granite. When formed with a limestone which has very few impurities in it, it will be white. Marble formed with more impurities such as clay minerals or iron oxides can be grey, pink, or black in colour. Traditionally Europe has been the largest exporter of marble, particularly Italy, where Carrara Marble is from, Greece and Spain, but more and more marble is coming from the Middle East and China. It’s quarried in a similar way to granite using a small explosion to separate it from the bedrock. It’s then cut in to slabs or blocks, and shipped around the world.
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