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3 Best Mohs Scale Test Kits: Test Hardness of Your Gemstones

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A Mohs hardness test is one of the most useful tricks in all rockhounds’ playbooks, but it’s sometimes hard to know which kit will help your specific application the most. I’m going to introduce a few of the best Mohs hardness test kits for different uses and budgets, and along the way, I’ll describe a little about what to look for in a Mohs hardness test kit.

The premium Mohs hardness test kit used by professionals and rockhounds alike because of its quality, completeness, and exactness is Minerallab’s Test Kit for Industrial Applications. The second is the TTC 6-piece Tester Set for its convenience. A budget or educational option would be the American Educational Products Hardness Collection with Test Kit. (Amazon links)

Kits that test for hardness come in all shapes and sizes, so depending on whether you’re a casual, die-hard, studious, historical, or thrill-seeking rockhound, you’ll be looking for different attributes that best suit your style.

Best Mohs Scale Test Kits: Test Hardness of Your Gemstones
Best Mohs Scale Test Kits: Test the Hardness of Your Gemstones

If you want to check out the best Mohs hardness test kits, you can find them only by clicking here (Amazon link).

Mineralab Mohs’ Hardness Test Kit for Industrial Applications

Many geologists and professionals, such as rock shop owners, use this test kit (Amazon link). It’s so popular among the experienced for many reasons, but to start it off is the kit’s simplicity. It takes the form of 4 double-sided and labeled pencil-shaped objects. 

Their thickness, color codes, and labels are conducive to field use – finding the exact tester you’re looking for takes hardly a second.

They are encased in a simple plastic mold that clings onto them and won’t let anything fall out if turned over. The encasement has a single simple latch and instructions on the minerals used for testing.

Each pencil is thick and has an abrasive texture, so they are easy to grip, even when wearing a pair of rockhounding gloves. The scratching tip is pointed and exact. 

The design is simple, ergonomic, and easy to use in the field. 

Using this Kit

This leads to one of the most important practical aspects of a Mohs’ hardness test kit: the scratching tip. As we can see, there are some kits that use only large stones for their hardness.

This can sometimes challenge a typical user when they want to test the hardness of a particularly small or valuable stone. 

A blunt scratching tip found on a device or a rock itself is a clumsy tool to use on a small stone, and if it is hard enough to scratch, it may leave a noticeable mark.

Therefore, the best tool to use has a pointed tip. Even if you have to view the mark with a jeweler’s glass (another invaluable instrument for a rockhound), it’s a clean scratch and not a big deal to the rest of the mineral. 

Test Quality

This set uses minerals of 2-9 hardness on the Mohs scale. It’s typical not to see Talc – the usual “1” referenced by the scale – in these kits because it’s regarded as the softest mineral and won’t scratch anything.

So, if gypsum – the two – can scratch a particular mineral, you can estimate that the hardness is between one and two. Diamonds are also commonly left out because nothing can scratch them, so if your corundum (9) cannot scratch your mineral, you’re probably looking at a diamond.


To wrap it up, this eight-piece set (Amazon link) is a winner among many because of its simple ease of use and durability. They are all made of metal, so if something breaks, it would be the case, but not for a few decades.

One possible con of this kit and its design is that kits are only as exact as the number of tests you can perform. There may come a time when you want to know whether a mineral is 5.2 or 5.8, and this kit, or any other on this list, will not be able to tell you that. You’ll need a more specialized device, and this one isn’t transportable.

Mineralab Mohs’ Hardness Test Kit for Industrial Application Rating

TIP: Knowing the Mohs hardness of your gemstones is always good. One of these situations is when you want to cut your rocks or minerals. Knowing Mohs hardness helps you to choose the right tool. Find out more about the best tools for cutting rocks in the article below:
What Can I Use to Cut Rocks? These 5 Tools are the Best!

TTC 6 Piece Hardness Tester File Set

This TTC set (Amazon link) was chosen as an alternative to the Mineralab testing kit because of its convenience in terms of time-saving and field use. Like the above kit, these pieces are color-coded and ergonomic. However, these tools are only single-sided.

Using this Kit

Regarding the human factor engineering of the kit, it may be slightly more comfortable for prolonged use (think of double-sided colored pencils vs. single-sided).

However, it involves more moving pieces and adding more things to keep track of. Generally, because of these two things, this kit loses out to the Mineral kit when it is meant to be used for on-the-go testing. Its usability measures up nicely for home and lab use.

Another interesting attribute of the TTC tester file set is that it’s just that – a file set. It works on a linear file type mark rather than a single-point scratch.

This has several implications. First, for smaller specimens, making a mark with a file-type tool might be less comfortable.

Second, the tool will wear down less, especially those with less hardness. Between a file type and a point type tool, there is no all-encompassing answer for which is better, but I recommend starting with a point tester if you’re unsure or do not have a preference.  

Test Quality

The TTC 6-piece hardness set also has another quirky attribute – it’s sorted and calibrated based on the Rockwell hardness for metals. Therefore, this is a perfect tool if you are more interested in the industrial use of minerals.

Many craftsmen working in industry or hobbyists working with metal use these tools to analyze different specimens. This toolset ranges from 40 to 65 on this scale (HRC). This corresponds to four to six on a Mohs’ scale – where many useful industrial minerals exist. 


In summary of this set (Amazon link), it is most useful for applications that involve minerals with industrial use such as iron or even man-made materials like concrete.

It is ergonomic because it is comfortable to use for extended periods, but it isn’t as easy to bring out in the field and isn’t as exact for smaller specimens like gemstones.

TTC 6 Piece Hardness Tester File Set Rating

TIP: The scratch test is one of the most popular options for testing the hardness of your rocks. Check out a step-by-step guide on how to do it in the article below:
Performing Scratch Test on Rocks (Follow These 8 Steps)

American Educational Hardness Collection with Test Kit

True to its name, this kit (Amazon link) is great for educational purposes – it’s hands-on and great for kids. It is also more complete in terms of what is included. Let’s take a look.

Using this Kit

This kit includes 9 minerals in their natural form – no tool form is added to make testing more comfortable.

Therefore, they come in 9 different compartments in a box and do not have any sort of case that facilitates field use. Diamond is a mineral that is not included; this set does have a talc specimen.

Because the minerals are in their natural form, you can see why this test kit is fantastic for an entry into the world of geology.

Each rock has a sticker corresponding to its hardness, and they can be used to scratch each other or other specimens to determine hardness.

This is also a great budget option for beginners – it’s just a fraction of the cost of the industry-standard tools. 

Test Quality

The value contained in this set is not just limited to Mohs’ hardness testing.

This kit includes more materials, such as a streak plate, to test the characteristics of minerals (a rock’s streak is a more objective way to test its color; to learn more about this, read the article about how to identify rocks). It also includes a nail and a penny to demonstrate how mineral hardness plays into our everyday lives.


In summary, this educational tool (Amazon link) is great for a beginner rockhound or to introduce someone to the spectacular world of rocks and minerals.

It’s also a good budget option for a rockhound who isn’t too interested in finding valuable gemstones but more in learning about his/her finds through investigating their properties.

American Education Hardness Collection with Test Kit Rating


To wrap it up, the Mineral testing kit (Amazon link) is the industry and Rockhound premium standard because it is exact and easy to carry with you and use in the field.

For rockhounds who are more interested in the geology of useful and industrial minerals, especially metals, the TTC file testing kit (Amazon link) is a great alternative to the Mineralab kit. The American Educational Hardness Collection and Test Kit (Amazon link) is a fantastic entry to the hobby, especially for the family.

TIP: The advantage of the hardness test is that it can be easily done at home or even in the field while rockhounding. Check out the step-by-step guide in the article below:
DIY Guide: Testing Mineral’s Hardness (Explained by Expert)