Those Most Awesome and Ugly Toned Coins
In most cases, natural toning of coins increases the value of coins when that toning enhances the eye appeal of the coin and presents the natural beauty of toning sequences. Similarly, ugly and especially false toning can detract from the eye appeal of a coin and decrease its value. In my opinion, a falsely toned coin might as well be a cleaned coin and most definitely decreases the value of the coin. False toning of coins is usually induced in an attempt to cover up an old cleaning or to ‘hide’ a distracting scratch or blemish on the coin. With some understanding of the natural toning processes that occur with coins one can easily determine a naturally toned coin from a falsely toned coin.
What is natural toning?
Natural Toning is a term that describes the naturally occurring oxidation and discoloration that forms over years on the surface of coins from natural chemicals in the air acting on the metal.
The type and colors of toning depends on a number of variables. Natural toning can take many months or years to begin and many more years to run its course.
What is False toning?
False toning is any induced or unnatural oxidation or discoloration of a coin from exposure to chemicals, induced heat or forced exposure to UV lights outside the normal realm of nature.
Similar processes to what cause toning or tanning of a person also occurs with all materials in our environment.
Natural toning on coins occurs when varying wavelengths of ultra-violet lights reverberate within the microscopic molecular pores of the coin and across the surface of the coin.
This reverberation includes the multitude of changing incident angles and subsequent remaining energy levels of the ultra-violet light waves as they dissipate in the pores of the coin and along the surfaces of the coin until all the energy is either absorbed or reflected back away from the coin. Similar to your old AM radio signal on your radio, the reverberations can propagate from pore to pore or creep along the surface of the coin.
In the case of your AM radio, this propagation is enhanced at night due to a more dense and counter-reflective atmosphere so the AM signals had lower incident angles and propagated farther. Thus, you could hear those far-away radio stations.
Similarly, the exposed areas of the coin will have more UV energy exposure and thus more toning ;whereas an area of the coin with its surfaces partially blocked will have less toning and areas of the coin that are covered by anything that totally blocks UV light (another coin, for example) will have no toning. This is where ‘rainbow’ toners come from. The same is true with tanning of our skin where we can get a ‘sun’ tan any time of year (changing incident angles and energy levels) depending on how long we remain exposed to the UV light and what we are wearing to block the UV light from our skin. Just as false tanning can be obtained at your local tanning facility, the same is true with coins. There are literally just as many falsely toned coins out there as there are falsely tanned people in our world. You can tell the difference.
Key natural factors influencing the type and sequence of toning include the strength and incident impact angles of the ultra-violet light and the continual and cumulative lengths of exposure to the varying wave-lengths (frequencies) and energy levels of the ultra-violet light. Other factors are specific to the item being toned.
Coins are struck from planchet materials that are mixed at different percentages, struck at different temperatures and under varying pressures. The mean density of a coin and the molecular makeup of the materials from which a planchet are produced are considered standard for any specific type of coin. However, the surface laminar density (the density of the molecular makeup of the coin’s surface layer depends not only on the metal composition but also the temperature of the planchet when struck and the machine pressure used to strike the coin. These variables and the resultant variations in metal flow during the striking process result in varying surface laminar densities. In general, the center of the coin will have the higher density as the metal flows towards areas of lower resistance, whether that be towards the rim or upward into the die recesses (designs) causing elevated surfaces on the coins. These elevated and periphery devices will have a lower resultant laminar molecular density thus impacting the type of toning they will be subject to.
This understanding is key in identifying falsely toned coins from naturally toned coins. For example, if you study a ‘rainbow’ toned coin and the individual colors as they cross devices on the coins you will notice the color shift out of line over the devices whereas the color differentiation line will remain straight on a falsely toned coin.
Periphery toning can be natural or false. So how do you tell the difference?
Natural periphery toning occurs with stacked coins with just the rim exposed. Some creep propagation can still occur between adjacent coin rims onto the obverse and reverse of the coin. The rim side of the periphery devices (outer edges of stars, lettering, etc) will have more exposure than the inner side of those devices while the mesas on those devices will not as they are nearly parallel to the incident angles of the UV light. Likewise, the inner recesses of the denticles on the obverse and reverse of the coin will have less toning as they are not subjected to direct UV light and only subjected to refracted and reflected UV light at lower energies.
False periphery toning from chemical leaching of dies and bonding chemicals used in production of coin storage books can make for some beautiful toning, albeit false toning. You can tell the difference by studying the inner recesses of the denticles and the die striation lines. If the periphery toning is nearly identical in the recessed areas of the denticles to what it is on the elevated denticles the toning is likely ‘leach’ toning, AKA false toning. Similarly, if the discoloration follows striation lines farther inward on the coin, although lighter in color as it leaches inward as the dies leach out onto the coin, or if there is an abrupt edge to the discoloration different from that of natural toning having occurred you have a falsely toned coin.
Other natural factors include the type of storage and the atmosphere of storage as each can influence and/or block UV light reverberations and propagation. For example, many Morgan dollars were stored in canvas bags for decades. Those coins along the outer perimeter of the canvas bags have a gradient of toning that has occurred due to the blocking effects of canvas. Where the weaves were most dense less UV exposure occurred. Where the weaves were less dense more UV exposure occurred. These ‘canvas’ toners, especially those where one entire side of the coin was adjacent to the canvas, are actually quite rare and beautiful.
For example, for a 90% silver coin to become a natural “Black Widow” (a deep black onyx color that looks like the black is ‘inside’ the coin and covers at least 90% of one side of a coin.), can take 15 or more years to occur depending on a number of variables. These are likely the rarest of all naturally toned silver coins and can command hefty premiums. These coins progressed through the many color sequences discussed below with continued UV exposure to get to this point.
For “Toner Enthusiasts”, most collect a variety of very colorful and naturally toned coins with a broad range of colors from gun steel blues, cinnamon browns, candy-apple reds, deep cherries, ‘Fenway’ Greens, brilliant autumn oranges, sunsets, kaleidoscopes, lavenders, burgundy wines and canvas and rainbows. Just as in any industry or hobby, the values of these ‘toners’ is dependent on eye appeal, technical grade, and supply and demand.
The following are just my guidelines and opinions:
‘Black Widows’ are the pinnacle pieces of toning. Deep pockets will likely be needed to acquire one.
The kaleidoscopes and canvas toners run a close second and third in my book due to the rarity of these pieces. Expect DMPL premiums for the grade.
Candy apple reds, deep cherries and ‘Fenway’ greens vie for the most stunningly beautiful colors and are also very rare when they cover 75% or more of one side of the coin. Expect closer (70%) to DMPL premiums. For example, technical grade value of $100, PL $200 and DMPL $500. 70% of the $300 difference between PL and DMPL is $210 added to the technical value of $100 results in a $310 coin value. For those with the same colors but less than 50% coverage expect PL premiums.
The rainbows are easily obtainable, relatively common and the most beautiful as they can display the full range of toning and the color sequences. Premiums range from PL to DMPL values for the technical grade dependent on percent coverage and orientation.
Perfect rainbows (at top of coin) and especially ‘rainbowls’ (bottom of coin) will be closer to DMPL values for the grade while the remaining rainbows trend closer to PL values for the grade with a percent coverage difference above PL as discussed above. For example, a 20% coverage rainbow would be 20% above the PL based on the difference between PL and DMPL. Learn the natural color sequence as it may keep you from buying a knockoff false toner.
The gun steel blues (PL +30%) autumn oranges (PL + 20%), lavenders (PL + 20%), purples (PL), burgundy wines (PL), sunsets (light gold & yellows & light oranges & pinks) (PL), cinnamon browns (PL) typically run in the lower range.
General toning characteristics of the metals in coins in use today
- Copper – orange to reddish-brown to full brown to dark brown to nearly black.
- Nickel – Some light blues and oranges.
- Silver– Full spectrum of colors as discussed above.
- Gold – Bright yellow to orange. Sometimes a reddish color.
- Manganese – Gold to brown. Sometimes a light orange and blue.
- Aluminum– Silver to iridescent blue and orange.