Three Practical Stone Tests You Should Know | 3 Ways to Test Natural Stone (2023)

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.

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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.

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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.

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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.

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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.


How do you test for natural stones? ›

ASTM C97 tests two critical natural stone properties: absorption by weight and density, or how “heavy” the stone is. C97 is one of the most important and widely used ASTM tests. The testing involves drying test specimens of the stone in a ventilated oven for 48 hours and then weighing them.

What are the different natural stones? ›

The three main types of natural stone found on earth are igneous, sedimentary and metamorphic; this classification is dictated by how the stone was formed over the course of the years – or millennia – and gives us interesting and useful insights on the qualities of that specific natural stone.

What are the durability tests for stones? ›

Crystallization test of stone is performed to determine durability in which a specimen of 50 mm diameter and 50 mm height is dipped into sodium sulphate solution for 16 to 18 hours and weighed. The change in weight indicates the decay of stone.

How can you tell the difference between natural and synthetic gemstones? ›

Five key differences between natural gems and synthetic gems:
  1. 1) Synthetic gems are manufactured in laboratories whereas natural gems are mined. ...
  2. 2) Natural gems tend to have more inclusions than synthetic ones. ...
  3. 3) Synthetic gems are usually more brilliant in colour compared to natural gems.
Jan 28, 2020

How can you tell the difference between real and fake stones? ›

An important thing to remember is that real gemstones are natural and because of this they are going to have flaws. Synthetic gems will look more perfect. Also, fake gemstones tend to sparkle and shine better than real gemstones, because real natural stones have been worn down through the environment.

How do you get a stone tested? ›

Urinalysis is a form of urine testing and is commonly used to diagnose and assess kidney stones. Urinalysis can include various measurements and assessments of a urine sample. For kidney stone testing, urinalysis often looks for: Microscopic traces of blood in the urine.

What is impact test for stones? ›

The stone impact test is a standardized test method for investigating the durability of coatings and is required in a wide variety of vehicle manufacturers' standards.?

How do you test for rocks and minerals? ›

Also called a scratch test, Mohs Hardness Test looks at whether or not a mineral can be scratched by another mineral. Mohs Hardness Scale has ten minerals of known hardness. You scratch your rock with each of these minerals to determine where your rock falls on the scale.

What are the three main types of stone? ›

There are three kinds of rock: igneous, sedimentary, and metamorphic. Igneous rocks form when molten rock (magma or lava) cools and solidifies. Sedimentary rocks originate when particles settle out of water or air, or by precipitation of minerals from water. They accumulate in layers.

What are the 4 types of stone? ›

The familiar stone types that are used today are identified through four categories: SEDIMENTARY, METAMORPHIC, IGNEOUS STONE, and MAN-MADE.

How do you identify different types of stones? ›

To identify your rock, first take note of its physical properties like color, luster, banding, layering, and grain size. Next, test for hardness and weight by running simple tests. Finally, compare the properties of your rock to those of known rock types while looking for other identifying characteristics.

What is the difference between synthetic and lab created stones? ›

Synthetic stones are produced by man in a lab and are also referred to as “lab grown" or "lab created." Although they don't occur naturally, synthetic stones have identical properties to their natural counterparts and are made by creating the exact same environment in which gems grow naturally.

What is the difference between lab created and natural stones? ›

The main distinction is natural gems typically have inclusions from the crystallization process — gases and other minerals mixing during the molten stage of stone creation. Because lab-created stones rely on a steady, controlled process of applying minerals, heat and pressure, they usually have fewer inclusions.

What is the difference between natural stone and artificial stone? ›

Artificial stone is 20-30% lighter than natural stone while each slab is identical in design. This makes the installation process easier and affordable. In addition, the overall cost may depend on things like the design and its application.

Do real stones change color? ›

Color change is an uncommon phenomenon, making all color changing gemstones very rare. There are only a handful of color changing gemstones including Alexandrite, Color Change Fluorite, Color Change Garnet, Color Change Sapphire and Zultanite®.

What are the two types of impact tests? ›

There are two main forms of impact test, the Izod and the Charpy test. Both involve striking a standard specimen with a controlled weight pendulum travelling at a set speed.

What is crushing test of stone? ›

i. A test of the suitability of stone to be used for roads or building purposes; a cylindrical specimen of the stone, of diameter 1 in (2.54 cm) and 1 in long, is subjected to axial compression in a testing machine. Synonym of: unconfined compression test.

What are 3 ways you can identify rocks and minerals? ›

Using Characteristics of Minerals to Identify Them
  • Hardness. The ability to resist being scratched—or hardness—is one of the most useful properties for identifying minerals. ...
  • Luster. Luster is how a mineral reflects light. ...
  • Color. One of the most obvious properties of a mineral is color. ...
  • Streak. ...
  • Specific Gravity.

What are 5 ways to test rocks? ›

Geologists use the following tests to distinguish minerals and the rocks they make: hardness, color, streak, luster, cleavage and chemical reaction.

What are the different types of mineral tests? ›

The most common forms of mineral testing are color, streak, luster, hardness, cleavage, density, transparency, and magnetism.

What is Type 3 stone used for? ›

Ideal for: Hard-standings, haul roads, building sub-bases, path/road/highway/driveway/patio sub-bases, SuDS aplications.

What were the 3 types of stone tools used in the Stone Age? ›

The Early Stone Age began with the most basic stone implements made by early humans. These Oldowan toolkits include hammerstones, stone cores, and sharp stone flakes.

What are the three types of rocks quizlet? ›

The three types of rocks are metamorphic, igneous, and sedimentary. Metamorphic rocks form when rocks are altered by heat. Igneous rocks are formed when magma hardens. Sedimentary rocks form when sediments are compacted together to become one.

How many natural stone are there? ›

8 types of natural stone.

How many different types of stone are there? ›

There are three major types of rock: igneous rock, metamorphic rock, and sedimentary rock.

What are the two types of stones? ›

There are two main types of stones: natural, and engineered. Natural stone can be sedimentary stones, or minerals formed from volcanic material. Either way, these stones possess organic elements that come to light in the Earth's surface through mining and quarrying.

What are the three main types of testing? ›

The different types of tests
  • Unit tests. Unit tests are very low level and close to the source of an application. ...
  • Integration tests. ...
  • Functional tests. ...
  • End-to-end tests. ...
  • Acceptance testing. ...
  • Performance testing. ...
  • Smoke testing.

What are 3 types of testing and 3 types of testing environments? ›

What Are the Different Types of Testing Environments?
  • Performance Testing Environment. ...
  • System Integration Testing (SIT) ...
  • User Acceptance Testing (UAT) ...
  • Quality Assurance (QA) ...
  • Security Testing. ...
  • Chaos Testing. ...
  • Alpha Testing. ...
  • Beta Testing.

How do I know if I found a stone? ›

Minerals can be identified based on a number of properties. The properties most commonly used in identification of a mineral are colour, streak, lustre, hardness, crystal shape, cleavage, specific gravity and habit. Most of these can be assessed relatively easily even when a geologist is out in the field.

How do you identify raw gemstones? ›

Examine the surface for imperfections or markings.

Surface imperfections or markings such as ridges, grooves, plateaus, pits, etching, or other defects are features that can help you identify a rough gemstone. Study the surface of the stone carefully and note any imperfections on the surface.

How do you test gemstones with vinegar? ›

To test your finds for calcite, place a few drops of vinegar on the surface. If the vinegar starts to bubble within a few minutes, the stones likely contain calcite.

What stone is green and black? ›

Crocodile Jasper – This stunning jasper mimics the appearance of crocodile skin with its green and black flecking. It is a very unique stone that certainly feels reptilian in nature.

What stone is green with orange spots? ›

Also known as heliotrope, bloodstone is the traditional March birthstone. This dark green, opaque chalcedony with red to orange spots is a variety of plasma gemstone.

How do you test the hardness of a gemstone? ›

You calculate Mohs Scale of Hardness by doing the Mohs Hardness Test. If Mineral B can scratch mineral A, then Mineral A is the softer of the two. By working through all the reference minerals, a stone can be placed on the Mohs Scale.

What is used to identify gemstones? ›

Spectroscopy analyzes the way light interacts with the gem. Researchers can identify a gem, and can often determine if it has been treated or is synthetic, by examining how it absorbs or transmits light.

Do rocks react to vinegar? ›

Vinegar, an acid, dissolves bits of a material called calcium carbonate in the limestone. This releases carbon dioxide, a gas that rises to the surface as a stream of bubbles. Rocks that don't contain calcium carbonate won't fizz.

Can you use baking soda on gemstones? ›

Baking soda is abrasive, which is why it's great for cleaning sinks and toilets, but that abrasive quality can scratch gemstones and precious metals.

Can you use vinegar to test rocks? ›

As a bonus experiment, you can test to see if any of your stones are limestone by submerging them in vinegar! Limestone is a type of sedimentary rock known for tiny air holes that make it extremely porous. Vinegar reacts with the rocks and these holes to create fizzy bubbles!


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