Calcium oxalate


I was looking at the outer skin of the onion also called tunic. I saw white rectangular shapes on it. I found out its called calcium oxalate crystals,  a colorless crystalline salt. I found many on the tunic of the onion.😀

I hope you enjoy my first time posting.

-vaishnavi (13 years)

7 Comments Add yours

  1. Manu says:

    Dear Vaishnavi,

    This is absolutely fantastic. I had never realized that we have oxalate crystals embedded right next to the plant cells. It’s a fascinating juxtaposition of organic and in-organic matter. I wonder how to cells enclosing some of the crystals deal with such a large crystal.

    The images are absolutely fantastic – what a beautiful post.

    Welcome to the Foldscope community? Next – you should also look at Ginger 🙂 Can’t wait to read your next post.

    Also, if you can post where you bought the “tunic” – I would love to see that.


    1. Vaish says:

      I will surly do that though I don’t like ginger I will experiment on it. 😀 I figured out Calcium oxalate is highly toxic and sometimes found in urine. It’s one of the causes for kidney stones. I am guessing that’s why we don’t eat the “tunic” (outer layer) of the onion

  2. laksiyer says:

    Dear @Vaishnavi.. Crystals have some very interesting geometry and you can look them up in any rocks and minerals book. Can we say what kind of geometry these calcium oxalate crystals might have by looking at them?

    1. Vaish says:

      Ill look into it 😀

  3. Manu says:

    Oh – speaking of geometry. To me; they look like little houses – just the roof. I can see two little roofs; one on the very top and one in the middle.

    I wonder if it might be possible to remove and isolate them from the cells without actually breaking the crystals.


  4. Cristina Bosch says:

    What a beautiful image! I had never seen those crystals before… so neatly shaped.

    1. Vaish says:

      Thanks Cristina I also found it amazing when I first found it … And I was shocked to hear how these crystals can be found in urine sometimes and cause kidney stones


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