How Granite Colors are Formed
Granite comes in a variety of colors. The most common are variations of pink, white, grey, and black. Stone marketed as “black granite” is likely to be gabbro, because granite by definition contains at least 20% quartz, which is not naturally black.
Granite is an igneous rock made up of a variety of minerals. It contains between 20-60% quartz and 10-65% feldspar. Mica, amphiboles, and trace amounts of other minerals comprise the rest of the stone's composition. The colors in granite come from these different minerals.
The pink color in granite comes from a higher percentage of potassium feldspar. Higher amounts of quartz and amphibole create the black and white speckled granite that is seen in many countertops.
White granite has a high percentage of quartz, which is milky white, and feldspar, which is opaque white. Amphibole creates the small black specks that are seen in many examples of granite. A 100% white slab is likely man-made quartzite.
Uncommon Granite Colors
Red, green, and light blue granite is made up of different kinds of feldspar. They're rather rare, often coming from specific quarries where conditions were right for these minerals to form. Natural pure white granite is also very rare.
"Black granite" is popular for countertops, but it's not actually granite at all. It's most commonly gabbro, which is an igneous rock that is similar to basalt. It is not quartz-based, but rather made of pyroxene and plagioclase, along with small amounts of olivine, which is dark green, and amphibole.
Pros and Cons of Different Colors
Dark granite countertops are very popular among homeowners for kitchens and bathrooms. They are bold and dramatic, and can be used to suit almost any style. Like any other stone, dark granite counters have their pros and cons.
The most obvious benefit of dark granite is their dramatic look. They create a great contrast and ambiance in a kitchen or bathroom, providing a great backdrop for everything else in the space.
One downside that comes with dark granite is that it often shows marks more easily. Fingerprints and water rings can show up more easily on the dark surface. However, an advantage is that they don't stain as easily as lighter colors, because they're less porous. They may only need a few coats of sealer, and some varieties may not need sealing at all.
Light granite has many variations, with different flowing or swirling patterns and differently-sized crystals creating a unique look. These variagated countertops hide messes better than a more uniform counter. This variation also means that they're more porous, and so they need to be sealed more frequently to prevent staining.
No matter which color you choose, granite countertops are a great complement to any kitchen or bathroom design. You can certainly find a color that fits your existing scheme, or you may find a slab of stone that is striking enough that you want to base the rest of your design on its unique look!