What Does Diorite Look Like?

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Diorite can be a fairly complicated rock for some people to identify.  Its difficulties are due to its ratio of contents not always visually looking consistent.  Its use in different applications of our life may also go unnoticed by many beyond simple remarks like “hey, that’s a cool looking rock.”  

Some of the most identifiable applications diorite will have may be when it is applied to landscaping, buildings, and roads.  Of course we can’t forget the notable shiny and glittery countertops in the home.  The appearance of diorite can be quite appealing to the eye if you are able to capture its sparkle.

Diorite is known as a granitoid type of rock, and it is thrown into this category with the rest of the granite type rocks.  Hence why the name diorite may not be well known due to you always just hearing it referred to as granite.  Especially when it comes to countertops.

Key Characteristics of What Diorite Looks Like

Diorite is an igneous rock that has a very specific look and appearance.  Once you can recognize this specific difference, you may be able to visually identify diorite even if the contents of the rock may vary in its look from the last one.  You can identify diorite by the following characteristics to look at:

  • Its salt and pepper look.  This is the most distinguishing feature for diorite.  It will have a speckled white and black look, like salt and pepper.
  • It’s not always just white and black.  The color of diorite may have off white and grays within its contents. 
  • It can sparkle.  With the inclusion of plagioclase feldspar and other minerals, crystallization can happen within the rock.  These visible crystal formations will reflect and sparkle in the sunlight.
  • It is a coarse rock.  Pieces of diorite, especially freshly broken pieces, will be a very coarse texture.  

Not all diorite will look the same.  At times there are more whites and grays with less black speckles within.  Other times they may even appear more uniform in its white and black inclusions. Additionally it can even look to have more black than white speckles within.

The key to initially attempting to identify diorite will be primarily based on seeing some sort of salt and pepper look.  Additionally, the sparkle you would get with the crystallization of the minerals contents within is a good visual cue.

  

Diorite – These diorite rocks have a very distinct salt and pepper look with shinny crystalline inclusions. They are also quite coarse.

Different Looking Varieties of Diorite

There are a few different named varieties of diorite, as well as varieties that may have no name at all.  Diorite varieties will consist of the contents within the rock and some by its appearance.  Some diorite varieties will include:

  • Leucodiorite, is a form of diorite that has less hornblende and less of the other darker minerals.   
  • Ferrodiorite, is a very iron rich diorite, that has a darker look and darker inclusions within it.  This relatively unknown type of diorite is mentioned to contain titanium.  
  • Orbicular Diorite, sometimes generally referred to as orbiculite, is a special and rare diorite that looks like a diorite rock with circular inclusions within its contents. 
  • Pink Marshmallow Stone, is a type of diorite with large pink feldspar inclusions.  These rare rocks are currently only found in Australia. 

Diorite is not considered a rare rock.  Some varieties of diorite are more rare than others, but in general, diorite is quite abundant and can have many different appearances of that salt and pepper look.

Different Look Between Diorite and Andesite

Diorite and andesite pretty much have the same chemical composition.  Despite this, there are some very good differences to help visually identify the two apart.  Some visual differences between diorite  and andesite are:

  • Diorite has white and black speckles, and andesite is a very gray rock and can have some white inclusions.  
  • Diorite will have visible crystalline inclusions, and andesite will not have any visible crystalline inclusions.
  • Diorite will be more coarse of a rock, while andesite will not be as coarse. 

The best distinguishing factors between diorite and andesite will be that andesite is a very gray rock sometimes containing white inclusions, with no sparkle of crystalline contents.  Also note, diorite will be a white and black, salt and pepper, looking rock.

Do not feel upset if you have difficulty identifying these two rocks apart.  Many samples of diorite and andesite need to be tested to accurately identify them.  They often vary visually so it is not uncommon to mistakenly identify them.

This Andesite is very gray with random inclusions and would be an easier one to not confuse with diorite.

Different Look of Diorite and Gabbro

Visually identifying diorite from gabbro can at times be very difficult.  Gabbro in many instances will often look similar to diorite in its contrasting light and dark appearance.  Some visual differences between diorite and gabbro are:

  • Diorite will have more white inclusions.  You will not see very white inclusions in gabbro like you would see with a good sample of diorite  
  • Diorite will have very dark to black inclusions.  Gabbro will often have gray, even dark gray, and an off gray appearance.
  • Diorite will have a stronger looking contrast of speckled light and dark.  A lot of gabbro can be very plain looking, not a lot of color contrast, and even look a little rusty brown.  

Gabbro can have some very good contrasting light and dark colors at times, but putting that next to a good specimen of diorite, you may really notice the difference. 

Aside from trying to identify andesite and gabbro, identifying diorite and gabbro can be quite difficult.  I’ve seen so many images online stating that a rock is gabbro when in fact it looks like a specimen of diorite.

From my experience, expect to get it wrong on occasion when identifying diorite from andesite, and also gabbro.  Many times though, the strong visual contrast of the lighter and darker inclusions in the rock will help you come to the concussion that you have diorite and not something else.

A somewhat dull specimen of gabbro. There appears to be some white contents within the rock, but for the most part a fairly plain gray looking rock. I would not likely confuse this with diorite.

Conclusion

I am not going to convince you that identifying Diorite is easy.  In my time spent looking at different samples of diorite, I am guessing I get it wrong on occasion.  

When you go online and compare images of diorite and other rocks, I can only imagine that you would think “How in the world do you even know?”  You would be right in making that question.  I think many also get it wrong online by showing a specimen and labeling it incorrectly.

For more information on the rock Diorite, visit my article: “All About Diorite“

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