Pentellic Marble: A Monumental Metamorphosis 

Walking around the Acropolis Museum, only one word came to mind: candescent. Surrounding me, and throughout the whole museum, was the most beautiful white marble you could ever imagine. It gleamed bright white and nearly flawless in the sunlight and I honestly felt like I could have been standing right next to Hercules himself. For my whole life I’ve been enraptured by history and the Earth, and the Acropolis is a perfect example of where those two meet for everyone to experience. As I walked around the museum taking in all the incredible stone work and intricate details, my mind kept wandering to the story of the beautiful marble that was used to build one of the most famous monuments in history. 

The day before I visited the museum, I went to the Acropolis itself and got to see its immensity with my very own eyes. I was awestruck: everywhere I looked were massive boulders the size of a couch and huge columns three and a half stories tall made of pure marble (Fig. 1). Some of the columns have fallen over and are being reconstructed and most of the friezes and the pediments sit in the museum for everyone to see up close.

So you might be reading this thinking “What even is marble?!” If you already know, then you must be super smart. But if you don’t, then you are just like me so don’t panic! Before coming to Greece last week, I barely had any idea about what marble was and how it is formed. So while sitting there looking at the amazing rocks, I was confused and curious about their story and how the heck they got all the way to the top of the Acropolis. 

 

Figure 1: Large slabs of Pentelic Marble at the Acropolis, aproximately 1m tall and 2m wide.

  

So let me give you the lowdown: Marble is a type of metamorphic rock . This means that at one point, the marble used to be a whole different rock altogether, limestone. Limestone is a type of rock that is formed on ocean floors out of the mineral called calcite, made from the compound called calcium carbonate that can be found in the shells of organisms or dissolved in the ocean water. The calcium carbonate falls to the ocean floor and is cemented together to form limestone over time (Step 1, Fig. 2). Sometimes it is pushed wayyyyy deep down in the earth’s crust and is exposed to intense heat and pressure (Step 2, Fig. 2). 

Now listen close because this is where it gets really good. When any rock is exposed to intense heat and pressure, it begins to change, cue the “metamorphosis” (Step 3, Fig. 2). The molecules within the limestone rearrange themselves into a new structure, forming marble [1]. It is important to note, though, that the makeup of the rock does not change because no other ingredients have been added; only the arrangement of atoms has been changed because we added heat and pressure.    

 

Fiure 2: Steps 1-5 putline the formation of marble.

 

So, once the marble is formed super deep down in the crust, you might be thinking “how in the heck does it get back up to the surface to be used to make  sculptures of horses and stuff?” Valid question. And the answer is simple: faulting. Yes, that is the same thing that causes earthquakes. A fault can be simply described as a crack through a rock where the sides have been offset by motion. Deep within the Earth, rocks are moving and grinding past each other causing faulting and the movement of rocks at the surface, uplifting rock from from the deep to our level. So that new marble was pushed back up to the surface for the Ancient Greeks to obsess over and build monuments out of (Steps 4-5, Fig. 2). (For more information about what goes on inside the earth, take a look at Micah’s blog post Tectonism in the Aegean)

The source of the marble for the Acropolis comes from quarries on Mount Pentelicus, about 21km NE of Athens and is rightly named Pentellic Marble. This marble is bright white, fine grained, and will take your breath away when it is polished. Sometimes it has veins of other minerals within it causing impurities. This specific marble oxidizes, or weathers, turning the surface into a light honey color creating a soft glow [3]. 

 

Figure 3: The Erechtheion from the south. The Carytids can be seen supporting the porch.


One of my favorite uses of the Pentellic marble is the Erechtheion (Fig. 3). Sitting north of the Parthenon, this building is much smaller in size and requires a closer examination to appreciate it entirely. At first glance, the building looks a little jumbled and confusing because it is built on two different levels, but that was the architects way of incorporating the landscape of the Acropolis. The Erechtheon was home to many religious relics and sights at the time, including the cult of Athena and her olive tree, the mark where Poseidon struck his trident, and the tombs of two mythical kings [4].

The real stars of the whole building, though, are the six beautiful Carytids of the south porch (Fig. 4). These are stone statues of beautifully clothed maidens that replace the columns of the porch where they stand [4]. They are carved to look as if they are draped in fabric and have the utmost detail in their clothing.

 

Figure 4: Five Carytids in the Acropolis Museum.

 

Although there are six Carytids in total, only five stand in the museum today. Number 5 was partially destroyed by a Turkish cannonball, but one platform remains empty. “Where is the sixth one?” you might ask. Well, basically the British did what they do best and stole one of the beloved Carytids and a bunch of the other marble statues and friezes from the Acropolis for their own museum in the 19th century [4]. As if they don’t have enough history and cool, museum worthy things of their own.

 

Figure 6: Detail in carved draping on a Carytid.

 

Today, the rest of the Carytids have been removed and put in the museum and are replaced by casts so that the originals can be protected and carefully preserved. Thousands of years doesn’t always look so good on marble, so the maidens have been under the laser for a major stone-lift. The modern laser technology is helping remove layers of soot and grime to help return the Carytids to their original glory. 2,500 years has never before looked so gorgeous. 

So who knew that marble could be used to make something so amazing like the Carytids? The ancient Greeks, that’s who. They may not have known all about how it was formed deep in the crust, or how faulting brought the marble back up to the surface. But they did know that the marble was drop-dead gorgeous when made into columns and sculptures, the Carytids being my personal favorite. The Carytids supported the south porch of the Erechtheion and most of them now reside in the Acropolis Museum. The Acropolis and the marble that constructs it is something so breathtaking and immense that it can only be properly appreciated up close and in person. So grab your passport, and make the “quick” flight across the Mediterranean to experience it with your very own eyes. 


[1] Marble. Geology: Rocks and Minerals. The University of Auckland, New Zealand. Referenced 06/05/2015.  http://flexiblelearning.auckland.ac.nz/rocks_minerals/rocks/marble.html

[2] Faults and Faulting. Saint Louis University. Referenced 06/05/2015. http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/faults.html

[3] Pentelic Marble. Museum of Fine Arts, Boston. Referenced 06/05/2015. http://cameo.mfa.org/wiki/Pentelic_marble

[4] Cartwright, Mark. 2012. Erechtheion. Ancient History Encyclopedia. Referenced 06/05/2015. http://www.ancient.eu/Erechtheion/

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13 thoughts on “Pentellic Marble: A Monumental Metamorphosis ”

  1. Holly – I LOVE your figure 2. It is wonderfully drawn and very easy to follow. Great job summing up a geological process in a reader-friendly and unique way. I also really liked how so much of your personality and sass came out in this post. Let’s see what you come up with next. 🙂

    1. Lisa- Thank you! I really enjoyed creating Figure 2 and it helped me understand the process better myself. I had tons of fun writing this blog post!

  2. Really nice post! I got hungry with all the talk about ingredients, heat and crust, and then I cracked when you ragged on Brits. LOL! It was really enjoyable to read this.

    Great job breaking down the geologic concepts, and good on you for cross-referencing Micah’s blog post too!

    1. Mike- Thanks so much. Metamorphism can be tricky to explain, so I’m very glad it was easy to follow!

  3. Holly, I loved how easy this post was to understand! You really taught me a lot about marble. There’s so much personality in your post and it’s awesome! 🙂

  4. Hi Holly,
    It was great to read your entry on pentellic marble. You managed to provide background information, provided information based on your visit, and incorporate scientific information as well. Your explanation of how marble is formed is a great way for non-scientists to understand something that could be very complex and could get students to tune out. I assume that your education background helps you in making complex tasks understandable without leaving out important and necessary information.

    Your explanation of the Carytids is a great way to move from the scientific explanation of how marble is formed to an explanation of how it was used. I am a bit unsure about your description of the British though (the fate of 6th Carytid). We might have our strong opinions on whether something was ethical or not, whether they took the statue without legal rights, and so on. If you want to go in the direction of calling them thieves, you will need to back up your statement with much research.

    Overall, wonderful entry that shows that you “have been there” and have experiences that beauty of the marble statues. Good luck with future entries.

    1. Professor Gruber,

      Thank you for reading my entry. I feel as if my education background does help with breaking down tough concepts for others to understand. Finding the balance without removing too much of the silence can be a difficult task to tackle though!

      Also, thank you for your comment about the British taking the Carytid. I see that I could have provided more information to back up my claims and will keep that in mind for further entries.

  5. Hi Holly,

    This a wonderful first post for a few reasons:
    1. Details that provide a visual for those of us not there with you.
    2. Visuals that helped provide further details that support your description.
    3. A writing style that is casually-formal. This kind of writing is not easy to do but necessary for informed blog-posts.
    4. An integration of the science with your observation. Your writing is in step with a teacher’s.
    I learned quite a bit and more importantly, your writing provided an experience. Experiential writing is a skill that requires practice. Well done!
    Your post left me wishing I had managed a way to get myself invited by Professor Skinner. 😦
    I look forward to the next post! 🙂

    1. NGBarron,

      Thank you for reading my entry and I’m so glad you enjoyed it! This trip has been amazing and taught me so much, and I’m thrilled that my experience can be felt by others though the blog post.

  6. Holly, loved your post! I wasn’t sure on how marble was made and your second figure helped me imagine how the rock forms. I also loved how much personality and humor you put into your post! It’s as if I can hear you talking. 🙂 Overall, good read.

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