Quartz countertops are even more unusual, though, as you’ll see.
What’s In a Name?
Companies that manufacture quartz countertops have been very clever with their naming. The word “quartz” represents one of Earth’s most abundant minerals. One well-known brand of quartz surfaces says that their product is “pure natural quartz.” The phrase admittedly has a nice ring to it. But how accurate is it?
Geologically speaking, a manmade quartz countertop is not pure natural quartz. The only thing that fits that criterion is quartzite, which truly is pure natural quartz. Manufactured quartz surfaces are mostly quartz, but they are not purely quartz. Depending on the brand and the color, manmade quartz surfaces are 70% to 93% quartz sand or aggregate, mixed with polyester resin, ethenylbenzene (also known as styrene), pigments, and other additives.
Manufactured quartz slabs are composed of three main ingredients: particles of mineral quartz, resins, and pigments. The quartz particles can vary in size from about 5 millimeters down to less than half a millimeter. Polyester resin binds the mineral pieces together. In some cases, the resin is mixed uniformly through the slab, and in other cases there are visible areas of resin, depending on the design. The same is true of pigments; some designs are the same color all the way through, while others have ribbons or accents of different hues, which are often meant to imitate the naturally occurring patterns in natural stone.
Manufactured quartz slabs are made by blending the ingredients, then pouring the mixture into a mold. Different manufacturers use different processes, but some combination of vibration, compaction, heat, and a vacuum are applied to cure the slabs from a slurry to a solid.
Quartz Countertops Aren’t Solid Quartz
Sure, in most Quartz (engineered stone) countertops there is some natural quartz (an igneous rock that is composed of oxygen and silicon atoms) in there, but saying that Quartz countertops are all natural quartz is like saying that all cars in an average parking lot are Chevrolets.
Fully 10 percent of the volume in a quartz countertop isn’t stone at all, but rather a polymeric or cement-based binder. And the other 90 percent? Crushed up waste granite, marble, and natural stone or recycled industrial wastes such as ceramic, silica, glass, mirrors, etc. And yes, maybe some actual quartz—sometimes maybe a lot of it. All this rock material mixed together and held together with binders is what gives a so-called quartz countertop the look and feel of stone.
More accurately, a quartz countertop should probably be called “engineered stone” or “compound stone”—terms that more accurately describe the way these products are created.
Quartz countertops may include greater or lesser quantities of actual quartz, but they include no solid quartz and likely have lots of other materials in them, as well.
Because quartz is man-made, it can be a less expensive option than quartzite for large, complicated jobs. However, it is not as heat or scratch resistant, and this makes a big difference in how the material performs in the kitchen.
Quartz comes in several color options, because pretty much any color pigment you want can be added in when the material is being made, so you can find quartz that looks fairly natural, like a real piece of stone would, or some that looks colorful and trendy, with obviously unnatural coloring designed to make a statement.