Quartz countertops are popular in modern kitchens and bathrooms due to their durability, aesthetics, and low maintenance. The key ingredient that gives quartz its desirable properties is silica. Here is an in-depth look at silica content in quartz countertops.
What is Silica?
Silica, also known as silicon dioxide, is a chemical compound comprised of one silicon atom bonded to two oxygen atoms. It has the chemical formula SiO2.
Silica is one of the most abundant minerals on earth and is found in various crystalline and amorphous forms. Quartz, the crystalline form of silica, is the second most abundant mineral in the earth’s continental crust after feldspar.
Silica is present in rocks, sand, clay, glass, concrete, bricks, stoneware, and many other materials. It is a key component of quartz countertops.
Silica Content in Quartz Countertops
Quartz countertops contain 90-94% ground quartz aggregate blended with resins and pigments. Of this:
- Quartz crystals are comprised of 100% silica.
- Natural quartzslabs contain up to 99.9% silica.
Therefore, quartz countertops contain approximately 90-94% silica overall.
Engineered quartz contains more silica than natural stone countertops like granite, which contains under 50% silica. The high silica content is what gives quartz its hardness and durability.
Why Silica is Important in Quartz Countertops
Silica has several properties that make it valuable in countertops:
Hardness
Silica has a hardness of 7 on the Mohs hardness scale, making it excellent for countertops that need to withstand impacts, scratches, and heat. The hardness comes from the strong bonds between silicon and oxygen atoms.
Durability
The high silica content gives quartz resistance to etching, stains, impact, and daily wear-and-tear. Countertops retain the glossy look and smooth surface for years.
Low Maintenance
Quartz requires very little maintenance compared to natural stone. No sealing is required and it resists staining. Simple cleaning with soap and water is enough for routine care.
Consistent Appearance
Since it is engineered, the color and pattern consistency in quartz is excellent. Silica provides durability to maintain the uniform look.
Versatility
Silica allows quartz to be formed into varied designs and patterns. It can mimic stone, concrete, metals and more. Rich colors stay vibrant.
How Silica Content Affects Price
Higher silica quartz slabs tend to be more expensive than lower quality slabs. However, the price depends on various factors:
- Brand – Premium brands use top-grade raw materials. Their processing also ensures minimum impurities.
- Source – Some geographic regions have higher purity quartz. For example, Brazilian or Cambrian quartz.
- Quality Control – Rigorous quality control during manufacturing reduces impurities and variation.
- Patterns/Colors – Intricate designs and rare colors increase costs due to additional processing.
- Thickness – Thicker slabs (2 or 3 cm) are costlier than thinner options. However, they are more durable.
- Supply Chain – Efficient supply chains reduce production costs, lowering price. Luxury brands cost more.
While higher silica content quartz is pricier, it also increases longevity and retains appearance better. The initial investment is worth it over time.
Optimal Silica Percentage in Quartz Slabs
For best performance, the silica content in quartz slabs should be:
- Minimum 93% for residential kitchen countertops used daily. Prevents excessive wear.
- Minimum 95% for commercial installations like restaurants. Provides extra durability.
- Over 97% for heavy duty applications. Gives maximum hardness to withstand heavy impacts.
Ideally, aim for slabs with >95% silica content. Reputable manufacturers mention the silica percentage or provide independent lab certifications.
How to Tell if a Slab Has High Silica Content
It can be hard for consumers to test the silica percentage on their own. But here are some indicators of high-quality quartz:
- Reputable brand with rigorous quality control
- Uniform, consistent appearance without variation
- Hard, non-porous surface that is smooth to the touch
- Sparkling crystalline flecks visible in the aggregate
- High density and weight (heavier than lower-grade quartz)
- Excellent glossiness and light reflection
- Minimal impurities or isolated darker spots
- Retains appearance and feels unchanged over time
- Backed by a long warranty (15 years+)
Carefully inspect slabs in person before purchase to assess quality based on these criteria. Avoid cheap quartz with lower silica content that may compromise durability. Paying more for proven high-grade quartz is worth the investment in the long run.
How Silica Levels Compare in Different Countertops
Here is a comparison of the typical silica content in popular countertop materials:
| Countertop Material | Silica Content |
|-|-|
| Quartz | 90-94% |
| Granite | Up to 45% |
| Marble | Up to 20% |
| Soapstone | Up to 20% |
| Concrete | Up to 85% |
| Laminate | 0% |
| Solid Surface | 0% |
| Stainless Steel | 0% |
Quartz has significantly higher silica than natural stone and other countertops. This makes it one of the best options for durable low maintenance countertops.
Is There Such a Thing as Too Much Silica in Quartz?
There is no upper limit for silica content in quartz. Even slabs with over 99% silica perform well.
However, going above 97% does not provide any real benefit. The ultra-high purity makes the material more brittle and prone to cracks during processing. This leads to higher waste and no practical improvement in real world performance.
For most homes, having 93-97% silica is optimal. It provides an ideal balance of hardness, durability, and workability during manufacturing. Reaching 100% silica is unnecessary for residential or commercial use.
Conclusion
Quartz derives its durability and performance from its high silica content in the 90-94% range. Silica levels over 95% are recommended for quality quartz countertops. While 100% silica slabs exist, they offer minimal practical benefit over 93-97% slabs. When choosing a quartz countertop, examine slabs carefully and opt for a reputable brand with rigorous quality control to ensure optimal silica levels. Paying more for proven high-silica quartz pays off in the long run through decades of beauty and hassle-free use.