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Three Practical Stone Tests You Should Know

In the world of natural stone, it can be a challenge to learn about all the different kinds of natural stone surfaces. If you have ever gone onto a slab yard to peruse the selection, you have seen just how many variations of stone are available. In this article, we will discuss three specific tests that can be very practical for natural stone professionals as well as natural stone owners. As we do, we will discuss some reasons why these tests are not only handy, but also very valuable.

Stone Scratch Test

The first test that we are going to discuss is the scratch test. This test is not unique to natural stone but it is extremely helpful in identifying a variety of stone materials. Why is that the case? Because sometimes two very different stones might look very much alike. However, the hardness is often times significantly different. And a scratch test is designed to determine how hard a stone is.

When Scratch Tests Are Needed

A scratch test is needed before you get the stone. Ideally before you even buy the slab you might want to either have one done or do the test yourself. Since the reason for the test is determine the hardness so you can confirm that the stone is correctly labeled, before you buy it is the best time. Finding out if you have a true quartzite can save you the time, money, and heartache of getting your countertop home only to learn that it is not actual quartzite at all.

How To Do A Scratch Test

Determining a stone's hardness hardness using a scratch test is pretty much just as it sounds. You scratch the stone using an instrument that has a predetermined hardness. In fact, companies sell scratch test kits designed for this purpose. You can do a Google search and find many online. Each tool has a measured hardness.

Begin by using a tool to try to scratch the surface of the stone. If it does not scratch the stone, move to harder tool. The tool highest number of tool that does not scratch the stone indicates how hard the stone is on the Mohs scale. Compare the actual hardness of the stone you test, with the known hardenss ratings of various materials and you can determine what the material actually is.

Natural Stone Water Test

Another test that comes in very handy for fabrication professionals and homeowners is the water test. This test is simply a measurement of how quickly a stone absorbs liquid. By testing the stone for "thirstiness", the tester learns whether the stone needs to be resealed.

Why Water Tests Are Practical

Water tests are very practical because there is a very important need to know a stone's absorption rate. Engineered stone, porcelain, and sintered stone surfaces are non-porous. However, a natural stone will "drink" liquid that gets on it.

Fabricators that are putting the initial seal on the stone perform a water test after treatments to determine when the stone is sealed well enough. Similarly, homeowners that are trying to determine whether their countertop needs to be resealed benefits from the results of water testing.

How To Do a Water Test

Performing a water test (or absorption test) is a simple process. All you do is simply pour some water on the surface of your natural stone. The faster the stone absorbs the water, the more it needs sealed. A key to protecting your natural stone is knowing when and how to treat it with granite and stone sealer. Keeping natural stone sealed can help them resist staining. checking your stone's absorption periodically is wise since various household liquids can breakdown the seal on a stone surface.

Stone Acid (Etch) Test

The third and final test that we will consider is the acid test; also called an etch test. This test is designed to tell you some very important information; information that you will want to know before investing in a high priced surface. An etch test has the purpose of indicating whether the stone under test contains calcium carbonate. This knowledge is valuable because of what it can help you do.

Why Do An Acid Test?

One of the primary reasons to do an acid test is to distinguish stones from each other. Just as the scratch test can help you find the hardness of an unknown stone, the acid test identifies the minerals in the stone. Thus, revealing what stone you are actually looking at. Some stone types have calcite, a crystallized form of calcium carbonate. Others do not contain this mineral. How the stone responds to the acidic liquid reveals what it is made of.

When used in conjunction with the scratch test, an acid test can help stone consumers differentiate stone types. For example marble and quartzite can sometimes be confused with one another because they look similar. This is important because of a common problem in stone labeling where marble is incorrectly labeled as quartzite.

How To Acid Test Stone

Performing an acid test is simple and effective. All you do is pour a small amount of acidic liquid (lemon juice or vinegar) on a small piece of the stone and wait a few minutes (up to 15 minutes). If the stone changes color or gets cloudy, Then the you have etched the stone. You will want to perform this test on a piece of scrap or in an inconspicuous area because if the stone etches, you will have a dull spot (if the stone is polished) or a dark spot. Etching can be 'removed' in a sense by using an etch remover on the discoloration. However, because of the nature of this type of discoloration it can take patience and a bit of "elbow grease" to correct it. So, if you do an etch test on a stone that is already installed, be sure you do it in an area that is not readily noticeable. And, you might want to have some etch remover on hand to correct the appearance after the test. Clearly, our recommendation is to do the test on a piece of scrap and not on an installed stone.

So there you have it. Three stone tests that can help you to assess not only the type of stone you have, but also whether your natural stone needs to be sealed. Having the ability to perform these revealing tests allows fabricators to verify stone types and prepare a slab for a customer if needed. So be sure you're familiar with hardness testing (scratch test), seal testing (water test), and etch testing (acid test). If you are, you'll be better equipped to prepare, maintain, and work with natural stone surfaces.