How to Tell Granite from Marble and Other Stone Types

 In Blog, Granite, Natural Stone, Rock Doctor

It has been estimated that there are as many as 9,000 different varieties of natural stone in the world, each one with its own characteristics, its own range of colors and grains, and its own strengths and weaknesses. These different types of stone can be found serving a wide variety of functions in homes and buildings all over the world.

While many natural stone surfaces may appear a lot alike if you don’t know what to look for, knowing how to tell them apart can help you to identify natural stone surfaces at a glance, which is a plus not only when you’re trying to pick the surface that’s right for your next kitchen countertop, but also when deciding what stone surface cleaning and polishing products to buy!

Stones are broadly divided into three main categories.

Igneous rocks are formed by the solidification of magma deep within the earth, and include common countertop materials such as granite.

Sedimentary rocks are created over time by compression. As other rocks erode and are then pressed down by the weight of the earth above them, they create sedimentary rocks like limestone.

Metamorphic rocks are typically sedimentary rocks that have been exposed to great heat and pressure, and include marble and slate.

All of the most common natural stone countertops come from one of these types of rock, but identifying the particular stone surface isn’t always as easy as it might seem. Here are a few tips to tell granite from marble, marble from quartz, and so on.

  • Granite is the most common kind of igneous rock in the world, and one of the most popular stone surfaces for kitchen countertops due to its beauty and durability. Most granite is made up of a combination of quartz, feldspar, and other minerals. As one of the most durable natural stones on the planet, granite is extremely difficult to scratch.
  • Quartz is another igneous rock that is often found in granite, but these days you can also find plenty of quartz countertops. Quartz countertops are not made from naturally occurring slabs like granite countertops, and are instead synthetically created by mixing crushed quartz with some sort of resin to bind the quartz crystals together.
  • Marble is one of the most common metamorphic rocks to be used in countertops, and can be easily identified by the distinctive veins common in most marble surfaces. These veins form when the marble goes through its molten phase, and are often composed of minerals like quartz, feldspar, or biotite, though not every slab of marble has visible veins.
  • Slate is another metamorphic rock that is sometimes used for countertops and other construction. It usually forms in large, relatively thin sheets and is generally lusterless unless coated with some sort of polish. Because of its high clay content, slate can often flake or crack unless it is specially treated.

 

All natural stones have a variety of characteristics that experts use to identify them. Luster, for example, describes the way in which a mineral reflects light. Hardness seems fairly self-explanatory, and is often measured by what is called a “scratch test.” Color in a natural stone comes from its mineral content, while cleavage describes the way in which a stone breaks or fractures. Finally, different kinds of stones react differently to different acids, which is why natural stones can be identified using an acid test.

While this may seem like a lot to keep track of, with a little practice and research you’ll find that you can begin to easily identify natural stone surfaces when you see them in homes, businesses, magazines, or even on TV. You can also begin to use your new knowledge to help plan your next kitchen or bath remodel, as well as when it comes to choosing the right stone surface cleaning and polishing products.

Fortunately, that last part doesn’t take a lot of practice. Rock Doctor’s full line of stone surface cleaning and polishing products are specially formulated to be safe for use on almost any natural stone surface, and you can find them at fine retail stores including Lowe’s Home Improvement, as well as participating Home Depot, Ace Hardware, Do it Best, and True Value locations.

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