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karin_mt_2

Countertop Geology, Part Six. Let's talk about rocks some more!

karin_mt
9 years ago

This is round six of the Great Rocks Thread!

Please post your rock questions here. I've copied the basic info about quartzite and marble here because this is the most frequent question.

Quartzite and marble are hopelessly (deliberately?) mixed up in the decorative stone industry. My point, aside from just loving rocks, is to help folks learn how to tell the difference between the two so you are not at the mercy of a sales rep when a multi-thousand dollar purchase hangs in the balance.

Quartzite is much harder than marble and will not etch when exposed to acids. You can tell the difference between quartzite and marble by doing the scratch test and the etch test.

Scratch Test
Take a glass bottle or a glass tile with you when you go stone shopping. Find a rough, sharp edge of the stone. Drag the glass over the edge of the stone. Press pretty hard. Try to scratch the glass with the stone.

Quartzite will bite right into the glass and will leave a big scratch mark.
Any feldspar will do the same. (Granites are made mostly of feldspar)

Calcite and dolomite (that's what marble and limestone are made of) will not scratch. In fact you will be able to feel in your hand that the rock won't bite into the glass. It feels slippery, no matter how hard you press.

PS - don't press so hard that you risk breaking the glass in your hand. You shouldn't need to press that hard!

Etch Test
Etching is when the surface of a rock is dissolved from acids like lemon juice, vinegar, wine, etc. It is the primary bummer about using marble in a kitchen. Etching is most noticeable on polished rocks. Etching is not prevented by sealers, no matter what you hear from the sales rep!

Doing the etch test is simple: bring home a sample of the rock and put lemon juice or vinegar on it. Even after a few minutes the results are usually obvious. Etched areas look duller and are discolored compared to the rest of the slab.

Some people get conflicting results with these two tests, but normally anything in the marble family will not scratch glass and it will etch.

Quartzite and rocks in the granite family will scratch glass and will not etch.

Super White, the rock that started this whole discussion, turns out to have small amounts of quartz in it. Not enough to make the rock durable, but just enough to confound your test results because it can kinda sorta scratch glass. Real quartzite really gouges glass and even makes a grinding sound as it does so. But Super White can scratch glass somewhat, in some cases. So always do the etch test too because even with a little quartz in it, Super White will still etch.

For reference, here are links to the other rock threads, in which many types of rocks have been discussed.

Rocks 101: The Lowdown on Super White

Rocks 102: Marble, Quartzite and Other Rocks in the Kitchen

Rocks 103: Countertop Geology: Marble and quartzite and granite, oh my!

Rocks part 4, Marble, Granite, Quartzite

Rocks part 5, Marble, Quartzite, and other favorites

With that, let the rock conversations continue!
-Karin

Comments (807)

  • karin_mt
    Original Author
    3 years ago

    Wow, that salesperson gave you a really lame answer to an excellent question. I'd seriously consider shopping elsewhere if this person can't even bother to learn the basic properties of stone.


    At a bare minimum, I'd see if you can get a sample to test. If they won't give you one, I'd suggest looking for something else. Good luck!


  • Marguerite Mastromatto
    3 years ago
    last modified: 3 years ago

    @karin_mt I am late to this thread and need help. I have been searching for months and found La Dolce Vita quartzite. The stone center told me it came from Australia, polished in Italy. I even remarked that it looks like marble. So, I researched and see it's Austral Dream and a marble from Australia, not a quartzite. Every other stone center near me (and there are a lot) have this labeled as marble. Two have it labeled as quartzite. My fabricator said it could be mislabeled. Quartzite is incredibly hard to fabricate (so it costs more), and they would know once the saw hits it. But, it would be too late to go back to the stone center. The stone center did not give me a sample, so I guess I'm going back with a glass tile.



  • Marguerite Mastromatto
    3 years ago

    @Tim Horn Did you purchase the Dolce Vita?


  • cpartist
    3 years ago

    my guess is it's marble.

  • karin_mt
    Original Author
    3 years ago

    A pretty good rule of thumb is if any dealer is calling it marble, it's probably marble. So my hunch is that it's marble.


    Unfortunately, quartzite is widely mislabeled. But fortunately, you are doing your homework!

  • Peke
    3 years ago
    last modified: 3 years ago

    Karen, do you know if quartz will scratch glass?

    I found 3 quartz remnants that did NOT scratch my glass tile. They looked like marble though. I also tried the scratch test on a quartz remnant that definitely looked like quartz, and that one DID scratch the glass tile.

    Yesterday, I found a marble remnant that DID scratch the glass tile. The fabricator could not remember the name of it, but he said they use that marble more than any other marble. English is a second language for him, but I think he understood me well.

    Quartz- this one did not scratch glass.


    The marble that DID scratch glass is below.



    The stone below did not scratch the glass tile.


    The stone below (2 pictures) did not scratch the tile glass.





    The stone below is quartzite, and it did scratch the glass tile. The fabricator did not know the name.



    Will any marble scratch the glass? Will quartz scratch the glass?

    For a scratch test, will a glass tile work as well as a glass bottle?

    Still trying to get samples. (Since January, they have been too busy to cut a sample of these remnants.)

    Thanks.

  • Peke
    3 years ago

    Karin, I just found your articles for the Natural Stone Institute. https://usenaturalstone.org/properties-of-quartzite/?utm_source=related-articles/


    I assume what some stone yards call "soft" quartzite is actually a sandstone or a dolomite. Some are just plain marble. I went to Scotland and saw Roslyn Chapel a few years ago and saw the statues of sandstone where each one showed the process of sculpting in sandstone. It is amazing how the castles made of sandstone have lasted for hundreds of years, yet the sandstone can be easily carved.


    Thank you for your information.

  • karin_mt
    Original Author
    3 years ago

    Hi Peke!


    Manufactured quartz will scratch glass, yes. If you try to scratch glass with a rounded edge of the quartz, it might not work. But it's harder than glass and should scratch it.


    In general, marble doesn't scratch glass, but marble can have pockets of quartz (the mineral) in it, so in some cases you can get certain areas of marble to scratch glass a little bit.


    A tile and a bottle are the same hardness, but a tile is just easier to work with, in terms of shape. But either one will totally work.


    The last stone in your photos looks like Macaubus quartzite or similar. Beware that some of those are having problems with porosity and staining. It's a gorgeous stone, but depends where you intend to use it.

  • Peke
    3 years ago

    Thanks, Karin. I will keep trying to get a sample. Is the Macaubus quartzite an Intermediate quartzite? Grainy? So may absorb water/stain? I have Sea Pearl in my kitchen. I am looking for a stone for my bathrooms. Love the explanation of sandstone vs quartzite. Perhaps that is why people use the words "soft quartzite"?



  • karin_mt
    Original Author
    3 years ago

    Right - the grainier quartzites are the ones that are more likely to absorb stains.


    The 'soft quartzite' thing came mostly from marbles mislabeled as quartzites. But since it's a giant myth, it's probably applied in all kinds of incorrect ways! :)

  • Marguerite Mastromatto
    3 years ago

    I searched Australia stone dealers and emailed two of them. They got back to me noting that Austral Dream/Dolce Vita and Austral Pearl/Dolce Vita White is a true marble. "The stone is quarried from the Pilbara region of Western Australia. It is a dolomitic marble with quartz veins and probably the reason many in the industry refer to it as a soft quartzite. It has the beauty of marble with many of the properties of granite as it is three times harder and less porous than the Carrara Italian Marble."

  • javiwa
    3 years ago

    I don't know when I last commented in this thread, but I'll again share my experience with Macaubus White quartzite, in case it helps anyone.


    After installation, I watched as my installer properly and thoroughly sealed all surfaces of the tops, to include side edges, any exposed undersides and inside the holes drilled for faucet and R/O dispenser. Because I'd experimented with a stone sample and two different sealers, I knew my porous tops would require two coats (Tenax Proseal). I waited 48 hours and reapplied the second coat myself.


    My heart absolutely breaks for those homeowners who are experiencing staining/bleeding issues, but I have experienced none (knock wood). Our tops were sealed March 2016; and even around the heavy use areas (sink and prep), I've not yet resealed. HTH.

  • Peke
    3 years ago

    Javiwa, pictures please?

  • javiwa
    3 years ago

    Well, shoot. I just posted eight pics w/ descriptions, and Houzz didn't post any of them. The frustration continues -- this is why I don't post here very often any more. OK, I'll try just a few at a time; sorry.







  • javiwa
    3 years ago





  • javiwa
    3 years ago

    Backsplash in process:



    Voila!





  • Marguerite Mastromatto
    3 years ago

    @javiwa Very pretty. Is that a little window in the backsplash in the last photo?

  • javiwa
    3 years ago

    Yes, one on each side of the sink.




  • Peke
    3 years ago

    Beautiful! The stone I am looking at doesn't look like yours, so I guess my stone is not White Macaubus quartzite. It did scratch glass, but I don't have a sample yet.






  • javiwa
    3 years ago
    last modified: 3 years ago

    Peke: I've noticed the veins and patterns in WM vary widely among slabs (that I've come across the internet, anyway). I chose my slab because of the more brown content as opposed to those dark veins: I really didn't want a busy countertop. Who knows? Perhaps it's my stone that isn't MW! :)

    This is an area where the darker veins are apparent. We ended up having the fabricator hone the surface (one of our many mistakes with this company), which toned down the busy.



    This is the original slab we selected, on display at the slab yard (Taj Mahal held up for comparison - way out of our price range!):



    We were told the fabricator was holding a piece from the same batch ("looks exactly the same!") at the shop. It turned out the slab we ended up had many more dark patches than this slab...another oh, well, moment. They were able to template around the darkest areas.





  • Peke
    3 years ago

    That stone is so pretty. I love honed and leathered stones. My Sea Pearl is leathered. I touch it all the time...pet it... People that visit will do it too. It is funny to watch them do it.

  • Peke
    3 years ago
    last modified: 3 years ago

    Javiwa, Houzz issues are driving me crazy, too! Their answer is that it is not a Houzz problem. Many others have posted about the same complaints. It started several months ago.

    I finally got a sample to test. It does scratch the glass tile. I will do the lemon test tomorrow, and I will test for porosity of water, ketchup, etc.







  • Szara Loring
    3 years ago

    I'm wrapping up a kitchen remodel and have my heart set on honed Montclair Vermont Danby for counters. Yes I know it is marble. I understand it will etch and scratch and chip. It may stain. I need a light countertop as my kitchen does not have a ton of natural light. My cabinets are modern - horizontal grain white oak. It's just me and my husband. Wine is not a huge thing at our house but there is often a weekend G&T or marg. We do a lot of cooking from scratch.


    I am reading that quartzite can also etch and stain. And I'm having a hard time finding one in my area that does not have a very strong linear pattern (ie macubus, etc). I'm trying to make the trade off of more maintenance and patina for something I love vs. something I can live with.


    Helpful suggestions or first hand experience is appreciated. Here is a slab of Danby we have considered.



  • Peke
    3 years ago

    I spent 40 minutes answering your questions, but Houzz lost it somehow. The page came up with my post missing. I will try again.

  • Peke
    3 years ago

    All stones are different. It depends on the process they underwent inside the earth. Some have lots of "stripes". If the stone was turned 45° or 90° and then cut, then you would see a different looking stone. Go by the stone's characteristics. Colors and striations will vary.


    I have had Sea Pearl quartzite for 8 years with no scratches or stains. It will dull a knife blade.


    A knife will cut into marble. Anything at all can leave a stain or scratch or etch. A drop of water left on the marble will be absorbed and could etch the marble.


    Search Houzz for " etches and stains on marble" or ask people to post pictures. See if you can live with them. They are difficult to photograph.


  • Peke
    3 years ago

    Here are 4 Classic White quartzites. All different.


  • Peke
    3 years ago

    Did you read the 6 pages of posts about rocks? It is worth the read. Karin has been most helpful.



    Go back to the first post on this page (#6), and you will see the above picture with real links to click on.


  • B N
    3 years ago

    We saw this Matarazzo a few days ago. The fabricator said it was quartzite but the distributor said dolomite .


    I used a knife and not a scratch on it , I also used lemon , ketchup, bleach and white vinegar and it didn’t etch .


    Not sure What the stone is and if I should even use it in our kitchen . Any thoughts ?





  • Peke
    3 years ago

    It also called Matarazzo Bianco Quartzite, Matarazzo Dolomite, Matarazzo Marmol.


    Take a glass tile and seemed you can scratch the glass. Try multiple locations, not just one. Try to rub the scratches off of the glass. If the scratches will not rub off, it is quartzite. Unknown level of quartzite until further testing is done.


    Then try to get a sample and put one edge in water for 15 minutes. Check to see how high the water has absorbed. If it only absorbs up to the water level, that is good. If it absorbs more than the water level, that is not good.

  • B N
    3 years ago

    @Peke Thanks so much , I will try the glass and water test in the AM

  • PRO
    Diana Bier Interiors, LLC
    3 years ago

    Szara, that is a gorgeous slab of Danby marble. I have had honed Olympian White Danby as kitchen counter tops for 6 years. It's my absolute favorite marble, and one of the densest. It does not stain, but it does etch and chip. Some days I love it and other days I wish I had gotten quartz. The saving grace is that it can be re-honed. But it is beautiful!

  • Szara Loring
    3 years ago

    @Peke Thanks so much for the detailed responses. I have read through the posts. Been following for quite some time. Nice to hear your first hand experience with Sea Pearl. I'm a bit limited with what is available in my local area, but I will take another look at white quartzites. It is hard to find them honed.

  • Szara Loring
    3 years ago

    @Diana Bier Interiors, LLC Thanks for sharing your experience. I think my own would mirror quite closely. I love Danby, but there are going to be days where I would second guess myself. My analogy is my sports car is a dream to drive except for when its snowing or when I have to drive down a gravel road. Those are the moments I wish I had bought that used jeep. :)


    If you have time, would you mind posting a picture of your counters?


    Some friends recently got white macaubas and talk about how quickly it absorbs and how they have had to reseal it several times in addition to the sealer that the installer applied. My first pick would be soapstone, but my kitchen does not have a lot of natural light and there is not enough stock in my area.

  • PRO
    Diana Bier Interiors, LLC
    3 years ago

    Hi Szara, Here is a photo of the kitchen when it was first finished 6 years ago. I'm not there right now so I can't post a more recent one. Anyway, the etching is only visible when the light hits the marble from a specific angle. I've never resealed it and have not had one stain. I have however, hit it with a bottle or a pot on occasion and have some fairly large chips. Oh well, it's a work surface, and I'm not going to beat myself up over it!

    Suburban kitchen · More Info


  • B N
    3 years ago

    Did the glass test! It passed .


  • speedlever
    3 years ago

    @szara loring Search this page for lavezzi. We installed that in our kitchen and I posted a few pics that you might find helpful. We found it was was quite a job getting educated about stone countertops. And that not all quartzite is really quartzite. Seems there's much confusion in the industry as to what really qualifies as true quartzite and what gets marketed as quartzite.

  • Peke
    3 years ago

    Beatrice, did you try to rub the scratches OFF the glass? Marble and Dolomite will leave a "scratch" that can be rubbed off the glass. I had several slabs fool me until I learned that.


    Szara- I hear ya! I live two hours from a stoneyard. You can imagine what the cost is if my local fabricator has to drive there and back with a stone. He only buys cheap ugly granite at his shop.

  • B N
    3 years ago

    @Peke - Yes, I tried rub it off and they wouldn't come off.

  • Peke
    3 years ago

    Woo Hoo! I bet you are so happy!

  • paigemaclean
    3 years ago

    I am in Connecticut and have been searching for white, cool/grey quartzite countertops. I came across something called Dumont from Brazil, but I haven't been able to find any information about it and am trying to make sure that I have not found something that is actually marble, but mislabeled. Does anyone know anything about this quartzite? Perhaps it goes by another name? It passed the scratch test. The yard would not let me do the other tests. Thanks for any ideas!





  • M M
    3 years ago

    @paigemaclean That stone looks similar to one that I loved that had three different names at three stone centers. What is the main coloring? Is there a little greenish/sage color?


  • paigemaclean
    3 years ago

    it is overall white/grey. It has some blueish tones and the veining has some brownsh/greenish, but it definitely has overall cool tones rather than warm.


  • Peke
    3 years ago

    My Sea Pearl had bluish tones that turned greenish once in my home. Will they give you a sample? My stoneyard did not so I took a chance. Did you see the chart Karin_MT made up? Maybe you could go by her description of the various levels of quartzite. Will they let you do a water absorption test?


    The crystalline quartzite is easy to spot. Look at the names on the right, find one in your stoneyard and look for the grains, cross bedding, crystalline structure to see which one comes closest to looking like your stone.


    You might try either lemon juice or vinegar on a small paper towel in a zipper bag or maybe you could use an extra small empty hand sanitizer bottle. Don't ask...don't tell??? Don't forget to test it in different spots on the stone, not just one spot. Same with the glass test...use different spots.





    Read this article that Karin wrote about telling white stones apart.


    https://usenaturalstone.org/telling-white-stones-apart/


    https://usenaturalstone.org/how-to-be-your-own-stone-sleuth/


    And this one is excellent. https://usenaturalstone.org/properties-of-quartzite/

  • Peke
    3 years ago

    Karin_Mt, I just watched your Ted Talk x Bozeman, and read your articles on USA Today and Yale Climate Connections. Great job!

    https://www.youtube.com/watch?v=9vOtHnd6QVs&list=PLsRNoUx8w3rNownKXhX9VhOlqZw1io8dK&index=6

  • paigemaclean
    3 years ago

    @Peke thanks, that is very helpful. I was able to do the scratch test (with a nail and a screwdriver) and it did not scratch so that seems promising.


  • Peke
    3 years ago

    It does.

  • Tracy
    3 years ago

    @speedlever hi! How is the Lavezzi quartzite holding up in your kitchen? This is the stone I am also considering, but they don’t have a sample for me to test. It looks the same as the slab you showed earlier in the thread. I’m interested to hear if you still love it, and if you feel it is high maintenance or as you expected :)


  • speedlever
    3 years ago

    @Tracy Hey there! We have been delighted with the Lavezzi. It has held up very well indeed and has required zero maintenance. I would buy it again in a heartbeat.




  • Tracy
    3 years ago

    @speedlever I am delighted for you! It is beautiful! Thank you <3

  • chestnut3
    2 years ago

    Karin_mt if you're still around, can you give me your thoughts on this stone? Dal Tile calls it Tahitian Cream quartzite but I think it may also be known as Nuage which I know is an intermediate/grainy quartzite. Others here on the forum have had good luck with it but I'm just trying to make sure I do all my homework before I make a final decision. I couldn't do an etch test but I did try to scratch it with a screwdriver and it did not scratch. What are the things I should be concerned with considering it is intermediate and grainy?