Message:

<p>[QUOTE=&quot;physics-fan3.14, post: 623533, member: 19165&quot;]Ok, first we&#039;re going to start with seeing the cartwheel. Go get one of your slabbed Morgan&#039;s (by a Top TPG - PCGS or NGC) and a strong light source. Hold the coin at an angle, so that it reflects the light. You should see the coin shining. Now, slowly and gradually, turn the coin. Notice the shine move? That is what we call cartwheel luster - if you turn the coin in the right way, the &quot;spokes&quot; of luster will appear to rotate around the coin like a cartwheel. Practice at this until you can see the cartwheel luster. Practice at this before reading the rest of this thread. Practice at this before buying anymore coins. If you can&#039;t see and discern luster, you can&#039;t properly grade, evaluate, or purchase coins. </p><p><br /></p><p>Now, what causes this luster? When a coin is struck, the metal flows up into the recesses in the die, filling out the details and causing raised areas, which we see as devices, letters, etc. As it flows, the metal wears on the die; because the metal flows the same way each time, it will wear &quot;grooves&quot; into the die. I say &quot;grooves&quot; because I can&#039;t think of a better way to describe it - in numismatic parlance we call them flow lines. These microscopic lines reflect light in every direction, causing the diffuse shine that we call luster. </p><p><br /></p><p>When a coin is cleaned, this microscopic surface of the coin is disturbed. Depending on the method used to clean the coin, different disturbances are noted. This is one way we can tell how a coin was cleaned - baking soda or dipping will affect a coin differently than a wire brush or polish or whizzing, some of the most common ways to clean a coin. </p><p><br /></p><p>There isn&#039;t really a single definition for a polished coin, its more of a catchall phrase, and can include wire brush, baking soda, or other methods. Whizzing, however, has a very specific meaning and a very specific look. Whizzing refers to when someone takes a rotating tool, such as a dentist&#039;s drill or a dremel, attaches a wire brush, sander, or polishing head, and goes at the coin. It gets its name from the &quot;whizzing&quot; sound this makes. If you are familiar with these tools, you can imagine the look this creates on a coin, although an expertly done whizzing can be hard to detect. </p><p><br /></p><p>Taking a brush to a coin (wire or otherwise) creates a much different look - similar to the first Morgan posted in this thread. It usually has a large number of parallel lines, or groups of parallel lines in different directions. Usually, these polish lines will go over devices - if a line goes from the field, over a device, and back into the field uninterrupted, you can usually safely bet that it is a post-mint hairline or cleaning mark. Notice also that cleaning lines are recessed into the surface of the coin - the wire brush is intended to move and remove surface metal. Distinguishing raised versus recessed lines in the surface of the coin is tricky, but with proper lighting and experience, you can do it. </p><p><br /></p><p>Both polishing and whizzing a coin have the same intended affect - to simulate original luster. This is why understanding luster, how it looks, and how its created, are so important - if you don&#039;t know what real luster looks like, you will never be able to discern artificial luster. </p><p><br /></p><p>When you hold and rotate a polished coin under the light, in the same way you held your slabbed coins, you might at first see something that strongly simulates natural luster. But continue to rotate, and notice how differently it behaves. On a cleaned coin, because the polish lines all go in the same direction, quite often the luster will apear very strong in a particular direction. You must hold the coin just right to see it sometimes, and sometimes it is immediately obvious. It will glow unnaturally, and I&#039;m sorry that I can&#039;t explain it better - but being familiar with natural luster, you will notice that it just doesn&#039;t look right. Experience is one of the best aids to determining this - hence my recommendation to examine and study numerous slabbed coins, to understand natural luster. </p><p><br /></p><p>Well, I hope that helps you, or whoever else might read it. The best thing to do is examine as many coins as you can that you know are original, then when you see an altered or cleaned coin, you will be able to spot it. Good luck!</p><p><br /></p><p>Jason, aka physics-fan3.14[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in