Slate vs Serpentine Comparison

One is a material that is used for a variety of differing applications. The other is perhaps one of the most misunderstood types of natural stone. Both though, have characteristics that make them appealing for use in design projects of various kinds. In this slate vs serpentine article dealing with natural stone, we will slither our way through the properties and performance of serpentine. At the same time, we'll consider why slating a project to make use of the stone carrying that name might be a good choice.

Why Compare Slate and Serpentine

One thing that you may be asking yourself is, "Why compare these two stones in the first place?" That is a good question. Perhaps the main reason we have decided to undergo the slate vs serpentine match up is that both are used for countertop surfaces. It is true that slate conjures up thoughts of other applications, but it is also used for flat surfaces (think billiards and old time lectures). On the other hand, the term "serpentine" might evoke the mental picture of a special belt in an automobile engine. Yet, this term is used in stone industry nomenclature too though. As we look at and compare slate with serpentine, we will mention some of the uses for each and we will consider what makes these two types of stone both similar and different.

Properties of Natural Slate

The natural stone referred to as slate is defined in some circles in the following manner: a fine-grained, foliated, metamorphic rock derived from shale-type sedimentary rock composed of clay or volcanic ash and is the finest grained foliated metamorphic rock.

If you are a geologist, that description might make sense. But, what about the rest of us? Let's describe this stone used for countertop surfaces using words that will not require a dictionary. We'll do it by discussing the properties of the stone.

Slate's Hardness

One of the main things to think about regarding a stone's properties is the hardness. This trait matters because it directly contributes to the durability of the surface it makes up. For example, the harder the stone, the more scratch-resistant the surface is. in fact, a "scratch test" is one of the main ways the hardness of a stone is determined. The hardness of natural slate, as with other stone types, is a range of values rather than one single hardness. Slate ranges in hardness from 5-6 on the Mohs scale (1 to 10) of mineral hardness. The midpoint of 5 on that scale means that slate falls into the category of hard.

Color Variants of Natural Slate

If you are familiar with some of the well-known applications for slate, you may immediately be thinking, "you can have it in any color, as long as it's green". While much of the slate available is a green hue, not all slate is green. The color of natural stone is determined by its mineral content. Therefore, slate forms in other colors as well. Gray, blue, and black slate can also be found.

Slate is Not a Pore Choice

As a general rule, slate has a low porosity. so much so, that slate is often times used as a material for roofing tiles in some areas. Remember though, low porosity does not mean non-porous. It simply means that the water will not seep all the way through the tiles. So, if you use slate as a countertop surface, it will still need to be cared for adequately to keep it stain resistant. More on this later though.

Serpentine's Characteristics

As the name implies, this natural material is usually some sort of green color. Yet as simple as the naming sounds, it is in reality, more complicated than that. You see, serpentine is not a type of stone. Rather, it is a label that has been placed on a group of various stone materials that have a green hue and are somewhat hard in nature. In fact, some serpentine is also called by the name "hard marble", which is a misnomer geologically speaking.

What's in a Name?

In the case of serpentine, its naming is somewhat related to the composition of the material. The term serpentine actually refers to a group of minerals that are green in color. The stone though, geologically speaking, is called serpentinite; similar to how "quartzite" refers to a stone composed of quartz. However, in the commercial stone industry, the last syllable of the name gets dropped and the stone is referred to using the name of the mineral group of which it is composed. So, the name of the stone is actually related to the mineral content.

Serpentine Hardness

Since the minerals in the serpentine group are many, the hardness of serpentine varies due to the particular mineral content of a given slab. As a result, one slab may measure at 3 and another slab might actually be a 6 on the Mohs scale of mineral hardness. This wide variety of hardness means serpentine's hardness generally ranges from 3-6.

Color Selection

In the case of serpentine, the saying mentioned earlier ("having it in any color as long as it's green") is actually true. Because all the minerals in the serpentine groups are some shade of green, the resulting stone is green. The question though is, which green? Well, there are many shades of serpentine and again, the are related to the mineral content and configuration.

Porosity of Serpentine

Like the variation in color, serpentine's porosity also varies due to the mineral content. This is a common property in most natural stone. Since natural stone slabs are composed of materials that differ in density and porosity, the slabs that they produce are also porous to varying degrees. The easiest way to test a slab's porosity is to do a water test on it.

Comparing Serpentine With Slate

Now that we have briefly talked about the properties of each of these materials, we can delve into the comparison of them. We will begin with the similarities and then we will transition over to the differences.

Effectiveness As Countertops

Believe it or not, either of these materials can be used for a kitchen countertop surface. Each is hard enough to resist scratching if you select your stone by testing the hardness. Since serpentine can be soft in some cases, you will want to definitely perform a scratch test on your slab if you elect to go with serpentine. Since slate is more consistent in its hardness, you will generally get a slab that is above 5. However, there is no harm in verifying the hardness of any slab. Especially since there are occasions where a slab is mislabeled.

The hardness of a slab will play a role in the tools needed to fabricate the stone. Hard stone demands diamond blades that are designed for cutting harder materials. The same is true for any core bits used to cut out the faucets and sprayer holes in a kitchen or bathroom countertop.

Design Compatibility

Depending on your design, one of the materials in this match up may be more fitting. For example, if you are putting together a project for a client and you are looking for a dark color, either of these may due if you are targeting the green hue. If you need a bit of leeway in your dark color choice, you may lean more toward the slate since it is available in a wider variety of colors.

Care & Maintenance

When it comes to taking care of a countertop, a couple of the big things to look at are the reactivity and the porosity. Porous stone absorbs liquids faster than stone having low porosity. For this reason, most natural stone surfaces are sealed using a stone sealer designed for natural stone. Both slate and serpentine benefit from sealer applications even though slate has low porosity. As we stated earlier, low porosity is not the same as non-porous. So, being able to keep any liquid on the surface of the stone, afford the owner the opportunity to clean up any spills that occur before they are absorbed.

When it comes to reactivity, the cleaner you choose to use could play a role in the appearance of the stone. But in the case of natural stone, an important thing to consider is whether the cleaner you use on a daily basis is formulated for natural stone. Some cleaners are destructive to protective sealers that keep water and oil from being absorbed into the surface. Therefore, using one of those destructive cleaners on a stone surface will remove the sealer the fist time it is used. Thus, we recommend using a natural stone cleaner on countertops made form slate or serpentine.

As we have seen in this article, whether the surface is made from slate or serpentine, there are pros and cons. Both materials are natural stone and they have similarities and differences. So, which one to use will depend primarily on personal preference. But whichever one of these is selected, it will provide years of use as long as it is cared for properly.