Cartwheels and the Cartwheel Effect on Coins

Learn How to Recognize the Cartwheel Effect on Coins

1881 PCGS MS-66 Morgan Dollar with Original Mint Luster
An 1881 Morgan Dollar with Original Mint Luster. Image Courtesy of: Heritage Auction Galleries, Ha.com

Definition Of Cartwheel 

  1. Cartwheel is a slang term for a large American silver dollar coin, usually a Morgan Dollar. The term was mostly used in the late 1800s and the early 1900s. Very few people refer to silver dollars as cartwheels anymore.
  2. The cartwheel effect is a term that describes the rotating, windmill like effect of light that mint state coins exhibit. The cartwheel effect is best known for appearing on Morgan and Peace silver dollars, due to the basically flat design of the coins, planchet size, and die preparation methods. However, the effect can be seen on nearly any mint state coin. The cartwheel effect is caused by flow lines that occur during the coin striking process, and the effect is somewhat fragile, disappearing as a result of circulation or the coin being cleaned. Coin collectors also refer to this as "mint luster".

    How to See the Cartwheel Effect

    To observe the cartwheel effect on an uncirculated coin follow these easy steps:

    1. Obtain an uncirculated coin. Large silver dollars such as the Morgan or Peace Silver dollars will show the cartwheel effect most easily.
    2. Use a desk lamp or other single bulb lamp in a dark or dimly lit room. Other light from fluorescent lights or windows may make the cartwheel effect harder to observe.
    3. Hold the coin approximately 18 to 24 inches underneath the lamp.
    4. Tilt the coin at various angles to the light. You should see a pattern of rotating lighter versus darker reflection of the light against the coin's surface as you tilt the coin. The cartwheel effect doesn't necessarily appear on all mint state coins, since the effect is dependent on various factors that come together during striking.

    Why Is This Important?

    The cartwheel effect is an important part in determining the condition or grade of a coin.

    As a coin circulates in commerce the highest points on the coin will come in contact with other coins and surfaces that will obliterate the flow lines that cause the cartwheel effect to appear. This is one of the first indication that a coin has seen circulation in commerce and therefore cannot be classified as uncirculated.

    Additionally, since the microscopic flowlines that cause the cartwheel effect are extremely delicate continuous chemical cleaning or some other abrasive type of cleaning of the coin will damage or obliterate these flowlines. Therefore, a coin may seem uncirculated  because all of its details are still intact, but improper cleaning has destroyed the flowlines and hence  the cartwheel will no longer be observable on that coin.

    Also Known As

    Mint luster

    Example Usage

    Morgan Dollars are nicknamed cartwheels due to the strong tendency of mint state specimens to exhibit this beautiful windmill-like effect.