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<p>[QUOTE=&quot;Tom B, post: 1821067, member: 11854&quot;]I am a chemist with earned degrees in chemistry and many years of practical lab experience.</p><p><br /></p><p>Luster is largely created by the reflection of light off of flowlines, which are typically produced during the minting process.&nbsp; If you enlarge the flowlines enough they might look like mountain ridges or the blade on a saw with each tooth being another flowline.&nbsp; These peaks have a greater surface area to volume ratio than the remaining body of the coin and both dipping and toning preferentially attack these flowlines, which after dipping reduces their height.&nbsp; This is the likely reason for reduced luster on repeatedly dipped or overdipped coinage.&nbsp; If a coin is dipped enough and the flowlines are obliterated then it will have reduced surface area.&nbsp; At that point the luster would likely be either greatly diminished or entirely burnt off of the coin.&nbsp; Also at this point the surface of the coin would look like a flat plain more than a mountain range.</p><p><br /></p><p>This next point might be viewed as counterintuitive or contradictory.&nbsp; By this time the coin has an overall smaller surface area to volume ratio than it had previously, which means it will have less exposed surface area to oxidize so it might accumulate molecules of toning <i>more slowly </i> than previously, but it will also have less microscopic oxidation on its surfaces so that those areas that are freshly stripped may tone <i>more quickly. </i></p><p><br /></p><p>My <i>anecdotal experience </i> with coins is that freshly dipped AU or MS pieces that are immediately placed into albums or envelopes will tone more quickly and somewhat more deeply, but that they do not appear to have as thick of a coverage as non-freshly dipped coins.&nbsp; Take it for what it&#039;s worth, but some of these debates remind me of how many angels can sit on the head of a pin.[/QUOTE]</p><p><br /></p>

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