5 Steps To Check The Quality of Your Granite Slab

Wholesale to Public

Granite Buying Made Simple

5 Steps To Check The Quality of Your Granite Slab   5 Steps To Check The Quality of Your Granite Slab

Wholesale to Public

Granite Buying Made Simple

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5 Steps To Check The Quality of Your Granite Slab

5 Steps To Check The Quality of Your Granite Slab   5 Steps To Check The Quality of Your Granite Slab

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In the past, granite was a rarer stone, imported from only a few select places. However, granite is now abundant, so your granite slab may be from a quarry just about anywhere. Because of this, there is natural variation in the quality, which might translate into the price you pay.

As a general rule, middle to high-grade granite usually comes from Brazil or India. Entry-level stones are more likely to come from China. However, it is essential to know how to check the quality of granite when you are shopping around. Knowing the characteristics of high quality granite will help you make a better choice.


You cannot determine quality on looks alone, but more elegant granite will also carry a higher price. Usually, more abundant stones have more basic colors and design palettes. Higher-quality slabs will be uniform and straight since it impacts functionality. Stone imperfections imply either a low-grade stone or poor care while cutting the slabs.

Grades of Granite

Grading granite makes it easier to pick out quality immediately. Some suppliers may refer to them as levels or have more specific grades, but three are the most common.

  • High Grade: This is the best granite you will find. It is thick, dense, and will last a lifetime. It’s typically priced higher due to its rarer veins and patterns. You will see more glitz and sparkling mineral deposits in the granite, making it truly shine.
  • Middle Grade: While it may be slightly thinner and less glittering than the high grade, you can choose from many colors and patterns. It will still have all the benefits of durability and style that you could want.
  • Builder or Commercial Grade or Entry-Level: This is the thinnest grade and often has plywood backings to support it. The thickness cannot withstand heavy use. The patterns and colors are more common as well. The cost may be tempting, but you will not get the same life out of this grade, especially with heavy use.

Since you may not be able to determine the grade of your granite immediately, there are five steps to check its quality:

1. Visual Assessment

You should do a once over, looking for any discoloration, chips or cracks, scratches or dings. You should be able to see a crystal-like structure in the stone. Have a straight edge handy to check that the edges have been cut straight. The corners should also be straight and sharp. Overall, the granite should have a uniform color and thickness.

While you are most concerned with the presenting surface, don’t forget to assess the underside of the granite as well. The back should not have any circular marks, indicating the stonecutter didn’t use water to cut it. Lastly, the granite should have a clear ringing sound if you strike it.

2. Checking Measurements

First, the slab measurements should be within one millimeter of your specified amounts. When you measure diagonally from corner to corner, both should be identical.

Always measure the thickness. 15 to 20 millimeters is the base requirement for any construction work. The thicker the granite, the stronger it is. Entry-level slabs often are thin and require a wood backing for reinforcement.

3. The Coin Test

Granite should be dense and hard. You can check the hardness by pressing the stone with a blunt, hard object. A coin works well. You should reject the granite if the stone chips or splits from your coin’s pressure. You can also check the polish quality with the coin. If you gently scrape the polished surface and scratches appear, the polish or sealant is of poor quality.

4. Porosity Level

You can check the porosity of your granite by dropping three to four drops of citric acid or lemon juice on top. If the slab absorbs the liquid quickly, it is highly porous and not a high-quality stone. If an excessive amount of calcite is present, the lemon juice will leave a white stain on the surface, indicating a lower quality granite.

5. Verifying Color

If the color isn’t uniform or you suspect some artificial color enhancement, a simple test will verify its quality. Dip a cloth in rubbing alcohol and then kerosene. Run it along a portion of the slab. If it changes colors, someone has used an artificial pigment to hide the actual appearance of the granite.

Granite quality may differ in shading, pattern, or slab design variation. You want to pick suitable slabs when investing in granite to last a lifetime. Your trusted granite supplier should verify the quality of the stone you choose, but these field tests can reassure you, even without any previous stone quality experience, if you have any doubts about your investment.