Smoky black is one copy of the cream dilution (CR) with black. The cream dilution mutation is found on the MATP gene. Cream is an incomplete dominant, meaning it cannot skip generations and one copy of cream looks different than two copies. Cream appears to hide on blacks as cream can only dilute chestnut/red and thus has no effect on black. Smoky blacks have dark skin and eyes. Many smoky blacks appear more faded or sligtly off colored, but many look like normal blacks. Smoky blacks can fade in the sun, often to a more severe level than regular blacks.
Due to smoky blacks often being visually indistinguishable from regular black it is often not known that a pony is a smoky black until it has been tested for cream or produces a foal that has the cream gene. In the absence of testing this is a common way to make the determination. There is a genetic test available for the cream dilution.
It is not known when the cream dilution was first introduced into Chincoteagues. The palomino Misty was foaled in 1946 so it would have been at some point prior to that year. It may have existed early in the breed as there are a few accounts describing ponies as dun. Dun is traditionally used to describe buckskins and the term is still used today in parts of Europe. A 1891 article in the New York City newspaper The Sun stated that the ponies "are most frequently black, gray, sorrel, or dun." Additionally the 1910 Pittsburgh Times stated that "White and dun-colored ponies are exceedingly rare." A 1923 St. Petersburg Times article described the ponies as "bay, gray, dun, black, and sorrel". Conversely Leonard D. Sale wrote in 1896 in The Horse Review of Chicago that, "I have never yet seen a grey, piebald, dun, or yellow purely bred island pony."