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<p>[QUOTE=&quot;physics-fan3.14, post: 2354739, member: 19165&quot;]Yes, fresh dies will have a certain character of luster. But even you cannot deny that, over the course of the die&#039;s life, the character of the luster will change. This is due to the wear on the die. There are two effects - the movement of metal, and the surface of the die. </p><p><br /></p><p><br /></p><p><span style="color: rgb(0, 0, 0)"><br /></span></p><p><span style="color: rgb(0, 0, 0)">An absolutely brand new, first strike die can and will produce cartwheel luster. </span></p><p><span style="color: rgb(0, 0, 0)"><br /></span></p><p><span style="color: rgb(0, 0, 0)"><br /></span></p><p><span style="color: rgb(0, 0, 0)">I have a degree in rocket science. We did actually study materials and manufacturing as part of our coursework, to better understand how to actually make the rockets. So yeah, this kinda is rocket science. </span></p><p><br /></p><p><br /></p><p><br /></p><p>J. Dannreuther, in the Official Guide to Coin Grading and Counterfeit Detection, 2nd ed., explains it like this: </p><p><br /></p><p>&quot;Luster is the result of light reflecting from the surface. As a coin is struck, the metal flows into the recesses of the die because of the pressure applied by the coining press. The metal flow is usually in a radial pattern, i.e., outward toward the rim. On some coins, these lines are all but invisible but are still present microscopically. … Mint State luster is categorized in several ways: flat (flow lines are invisible to the unaided eye, as often happens when coins are struck from worn dies), satin (flow lines may be slightly visible but there is little cartwheel effect), frosty (flow lines are usually visible with a cartwheel effect, ranging from slight to heavy), semi-prooflike (light flow lines may be visible but most are not, being replaced by slightly mirrored fields that have a slight cartwheel effect), and prooflike (no flow lines are visible, with the fields now mirror-like, but with virtually no cartwheel effect).” </p><p><br /></p><p>I disagree with a bit of what he says here. First, I have seen many late state dies which produced strong luster. It is usually &quot;coarser&quot; than your typical early strike coin, but often seems &quot;brighter.&quot; Second, proof and prooflike coins absolutely have flow lines visible. Their lines generally appear more &quot;in&quot; the surface of the coin, rather than &quot;on&quot; the surface (if that makes sense). The word I like to use is &quot;chatoyancy.&quot; Take a look at a Tiger&#039;s Eye gemstone, or similar gem. There is a certain amount of luster &quot;inside&quot; the gem, even though the surface is polished and mirrored.[/QUOTE]</p><p><br /></p>

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