Can anyone explain what striation is to me please?

Discussion in 'US Coins Forum' started by zaneman, Jan 15, 2006.

  1. zaneman

    zaneman Former Moderator

    I heard this term, and I'm not sure what it means, but I would certainly like to know.
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  3. Leadfoot

    Leadfoot there is no spoon

    I've heard striation used in reference to parallel lines/scratches/polish lines. Most often referring to polish lines.

    Here is an example:


    See the die polish lines in the recesses? These are often called striations.

    Here's another coin that shows this feature:


    They are vertical in most of the fields of this coin.

    Hope this helps...Mike
  4. satootoko

    satootoko Retired

    ;) :)
  5. Skylark

    Skylark Senior Member

    Well a striation is one of many parallel lines
    In coin lingo its lines caused by the polishing of blanks prior to striking.
    They are usualy found on Proof coins.

    GDJMSP Numismatist Moderator

    Striations are something that have been with us as long as coins have been made. The dime pictured is an excellent example. On some coins the marks will be much more evident - on others there will be none at all.

    I suppose that in some cases they could be the result of planchet polishing but I think it would be a rare exception. For most marks on a planchet are obliterated by metal flow when the coin is struck. Striations and flow lines are not the same thing.

    Just as an example of how long striations have been around, here is a Ventian ducat struck in 1400.

    1400 Venetian ducat obv.jpg 1400 Venetian ducat rev.jpg

    Last edited: Oct 31, 2019
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  7. zaneman

    zaneman Former Moderator

    I have a morgan dollar, which I thought was cleaned, but had wondered about it, since the "scratches" could only be seen with a 10x loupe, and also were completely parrallel, would be it be acceptable to assume that there is at least a possibility that these striation lines? I sent the coin to be graded, so I'll found out if it's cleaned.

    GDJMSP Numismatist Moderator

    It's possible they are striations, also possible they are flow lines, and it's possible the coin has been whizzed. All three things produce parallel lines.
  9. zaneman

    zaneman Former Moderator

    I don't think it's whizzed, as I actually have a morgan dollar that was slabbed by and labeled whizzed, and doesn't look quite the same. Could you please explain what flow lines are to me? Today has been a good day for learning!
  10. Magman

    Magman U.S. Money Collector

    oh, this explains the lines on some of the coins in my proof sets :)
  11. GDJMSP

    GDJMSP Numismatist Moderator

    Flow lines are just what the name says they are. When a blank planchet is struck, it's flat, except for the raised rim. But when the dies strike it with thousands of pounds of pressure the metal of the planchet actually flows - it moves to fill all the recesses in the die. And when the metal moves across the surface of the die it creates flow lines on the surface of the newly struck coin.

    This is an exaggerated example, but imagine a glacier moving across the landscape. The bottom of the glacier isn't smooth, it's rough and jagged. So as it moves across the land it cuts into the land and leaves peaks and valleys.

    The same kind of thing happens when a coin is struck but to a much smaller degree. The surface of the die isn't perfectly smooth even though it has been polished. There are still very shallow valleys and ridges in the die and as the metal moves across these a mirror image of them is created on the surface of the coin. It is the flow lines created that produce the luster of a coin.
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  12. OldDan

    OldDan 共和党

    Here is the definition that I use;
    Works for me!
  13. Conder101

    Conder101 Numismatist

    There are also planchet striations that are long parallel marks left on the planchet strip from the stretching of the rolling process (and from the rollers themselves if they are becoming worn.) These striations can often be seen in the high relief areas on coins that are weakly struck.
  14. bruce68901

    bruce68901 New Member

    Wow I learnt some thing new . This is great group
  15. longnine009

    longnine009 Darwin has to eat too. Supporter

    Flow lines are etchings in the dies from the planchets moving across it. They are microscopic and are what gives a coin it's luster. Die polish or die scratches are just that, scratches in the dies (but bigger heavier scratches than flow lines) from sand paper or something pretty abrasive. The scratches are cut into the dies and so are raised on the coin. Dies are "polished" usually to reduce damage from clashed dies.

    Hairlines are scratches on the coin put there after the coin was struck. Die polish were scratches on the dies, and so, are imprinted into the coin. They are raised and will also have a color similar to the rest of the coin. Hairlines are scratches cut into the coin and their color will not resemble the color of the rest of the coin. If you scratch a piece of existing metal the scratch stands out. Hair lines will stand out as well, from the rest of the coin. Usually just rocking it will be enough to see hairlines. Offer to sell a BU coin to a dealer and rocking it slightly will probably be the first thing he does.
  16. GDJMSP

    GDJMSP Numismatist Moderator

    Is this how you intended to word this longnine ?
  17. longnine009

    longnine009 Darwin has to eat too. Supporter

    Thanks GDJMSP. That might be a good reason for using the term die polish instead of die scratches, too easy to get it mix up with hairlines scratches.

    Or we could petition congress to appoint an Entanglement Czar? When they come back from their Christmas Vacation :headbang:
  18. GDJMSP

    GDJMSP Numismatist Moderator

    No problem pal - I didn't think that's what ya meant since I know you know better. But not everybody else does - I was trying to avoid confusion ;)
  19. SawtoothJack

    SawtoothJack New Member

    What about when the lines shoot directly outward, instead of circling? Kind of like a starburst pattern. I have a Washington dollar coin with these lines right next to the Statue of Liberty. It looks like it’s only in the field. I also have a US cent with very heavy markings of the same sort, but it covers the whole obverse (Not just the field), and the coin is even bent into a dome shape. while they look stretched in some places on the rim, a portion of them look absolutely uniform. What are these types of errors called, and what causes them?
  20. micbraun

    micbraun coindiccted

    Yay! Another 10+ years old thread resurrected :)
  21. paddyman98

    paddyman98 I'm a professional expert in specializing! Supporter

    A worn die strike.. Spend it.
    slackaction1 likes this.
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