Granite composite sinks are among the best-selling and most popular kitchen sinks in the industry. They have enviable properties that make them stand out among other material sinks in terms of resilience, durability and functionality.

However, most people are often confused by some of the information available about quality sink materials. As a result, composition and production statistics are a hot topic.

In this article, we will explain certain terms to help defuse the ongoing debate - What is the most key factor of to determine a quality granite composite sink. Let's look at the composition of granite sinks and what the quartz content means in terms of hardness.

How are granite sinks made?

Two primary materials are used in the production of granite composite sinks: quartz sand (granite particles) and resin. These two materials not only make the sinks durable and resilient, but they also make them safe and healthy when serving food.

Thus, quartz sand is naturally a food grade material and does not contain toxic elements. In addition, the resin used (PMMA) is a raw material for artificial teeth, which means it can be used very safely in consumer equipment.

In addition, the manufacturing process for granite composite sinks may vary, as most manufacturers may adjust the amount of material used. For example, some manufacturers claim to use higher quality materials to increase the price of their products.

They advertise granite sinks with more than 95% quartz sand in order to get a higher price. This brings us to a further question - does a higher content of quartz sand make a granite sink better?

This is a misleading factor that influence the customers when buying a granite composite sink.

A higher percentage of quartz in a granite sink may not be better because it also contains a sufficient percentage of resin. Considering that you can perform several hardness tests on sinks, granite bowls may not be as strong as most manufacturers suggest.

Hardness only represents one aspect of a good quartz sink; the key factor in determining the quality of a good sink should be its density. (We will explain the reasons for this in detail below)

Is the source of quartz sand important?

Almost all granite composite sinks are made from quartz sand or so-called granite particles. More products from Chinese manufacturers use locally obtained quartz sand for these sinks. Thankfully, the quality of quartz sand from China is as good as foreign standards. This is because China is one of the leading countries in the production of quartz sand.

As a result, some factories have increased their prices by using imported quartz sand( from Germany or Italy). However, granite composite sinks made in China have never been questioned due to the poor quality of the raw material quartz sand. On the contrary, the quartz sand made in China is as good as the quality of the sink made from imported materials.

For this is not the main factor to determine a good quality granite sink. The manufacture process determine the density of a granite composite sink, which is the reasons to its stain-resistant and non-porous properties. 

Why is density a key factor in a quality sink?

Generally speaking, the higher the density of a sink, the better its resistance to scratching and abrasion. Therefore, the higher density of the granite sink, represents a better quality.

The density of a granite composite sink is determined by its production process. Previously, we wrote an article on how to calculate the density of a sink and use its density to reflect its manufacturing process.

Density should be the most important factor for making a quality granite sink

Of course, quartz cannot be scratched, but granite sinks can be scratched even if they contain 90% quartz sand due to resin additives. Therefore, you can see the resin particles falling out of the granite sink when scratched, but without scratches.

The best composition ratio of a granite composite sink

The best ratio of quartz sand to resin should be 80:20, not the higher quality of quartz sand content is better. Once the quartz sand content is too high, it will be more likely to crack during the production process because the resin acts as a binder.

Final Word

Granite composite sinks lead the industry in both aesthetics and functionality. However, most buyers want to know the quality of the product they are buying. Therefore, they tend to argue that the hardness of granite composite sinks is related to the quartz content.

The above explains in detail the hardness of granite composite sinks and the influence of other constituent materials. It clearly answers the question - higher quartz content does not make a granite sink better, a reasonable ratio (80:20) does.