Black (E) is one of the base colors. Ponies are black, chestnut, bay, or brown with other colors diluting/modifying the base color. Extension and agouti form the basis of all equine color. Extension determines whether or not a pony has black or not and agouti determines where it will go. Black horses have the dominant form of extension and the recessive form of agouti.
Many blacks do not look true black due to sunbleaching or fading, which are known as fading blacks. The best way to determine if a horse is black or not is to look at the muzzle. If the horse is sunbleached but the muzzle is still black it is most likely a black. If the muzzle is brown than the horse is a bay or brown. Blacks often have red streaks in their manes and tails from the sun. The winter coats of blacks often fade in the sun.
Blacks can be born as either an obviously black color or as a greyish black color. Foal coats often fade badly and black foals often look brown instead of black until they shed the foal coat.
Black is likely an original color in Chincoteagues as it is widespread and the breed was originally all solid dark colors. A 1891 article in the New York City newspaper The Sun stated that the ponies "are most frequently black, gray, sorrel, or dun [buckskin]." Leonard D. Sale wrote in 1896 in The Horse Review of Chicago that, "The prevailing colors are bay, brown, chestnut and light sorrel. A Washington Post article from 1902 stated that the prevailing colors were bay and black. A 1912 Baltimore Sun article stated that the ponies were "black for the most part". A 1923 St. Petersburg Times article described the ponies as "bay, gray, dun [buckskin], black, and sorrel". A Delmarva Star article describing the 1930 Pony Penning described the ponies as "many colored", with blacks, browns, bright bays, and so many with spotted coats."