Pretty (expensive) blue rocks?

Discussion in 'Sharpening Station' started by Bert2368, Feb 13, 2019.

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  1. Feb 13, 2019 #1

    Bert2368

    Bert2368

    Bert2368

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    I was looking at blue stones said to be from an island mine under the sea (or NEAR the named island? The phraseing here may be lawyer approved).

    Says they can't dig up any more of them, so you have to buy yours NOW. And they come with a natural leather pouch, non slip mats and have beautiful gold stamped kanji, heck of a deal.

    They are all so SQUARE. Not disorderly, live edges, cracks, inclusions? Almost like an artificial stone???


    Screenshot_20190211-140651_Amazon Shopping.jpg


    Screenshot_20190211-140516_Amazon Shopping.jpg


    https://www.amazon.com/Masuta/b/ref...8152243011&field-lbr_brands_browse-bin=Masuta
     
  2. Feb 13, 2019 #2

    KingShapton

    KingShapton

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    As I know, the so called "Ocean Blue" from Tsushima Island is very fine, estimated about 12.000 Grit.
    I think it is much to fine for the most knifes. Sure, it can be much joy to play with.
     
  3. Feb 13, 2019 #3

    chinacats

    chinacats

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    Pretty sure that you'd want to use it on a razor rather than a knife.
     
  4. Feb 13, 2019 #4

    KingShapton

    KingShapton

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    I have some natural stones from the UK which are also so fine. sometimes I use them with a knife, but that's just play.
    Just to see, how sharp can I get the knife.

    The big advantage of natural stones is, some of the produce some bite even though they are so fine.
    But sure, the edge won't last long.
     
  5. Feb 13, 2019 #5

    Badgertooth

    Badgertooth

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    I agree that this is Tsushima but mine won’t have been any more than abt 5k.
     
  6. Feb 14, 2019 #6

    mikaelsan

    mikaelsan

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    I think I recall recently watching a video with a razor guy taking about them, they should very a but in hardness and fineness. It I remember right the more blue stones are supposed to be coarser then the darker almost black ones, or was it the other way around? I think he talked about one being somewhere around 5000 and the other bring closer to 10000.

    I know that pretty vague, but there should be a fair bit of variation between the different Tsushima stones, the main thing in common should be that they are fairly hard, clean and uniform in colour and grit? Maybe someone who has actually handled one/some can verify
     
  7. Feb 14, 2019 #7

    KingShapton

    KingShapton

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    There are two types of mines. One is on Tsushima Island and the other is a underwatermine. And also there are two types of stones, one frpm the island, the other from the underwatermine. One is the more blue stone, called "Ocean Blue", this stone is very fine and the other one, the darker, almost black one, called "Tsushima Nagura" is less fine, it is about 5.000 grit.
    I guess that Badgertooth has one of the darker ones, the Tsushima Nagura.
     
  8. Feb 14, 2019 #8

    inferno

    inferno

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    From what I have read none of the tsushima stones are more than lets say 5-7k or so. Some may be as low as 4 I think I read somewhere. Also these are not usually liked some some reason. I think the main use is as naguras.
     

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