
With the launch of the iPhone 7 in 2016, Apple debuted a new "Jet Black" color, which was a glossy, shiny finish that was a departure from the standard brushed aluminum finishes of the iPhones that preceded it.

Jet Black was unique because of how dark it was in comparison to other "black" and "space gray" finishes at the time. Apple hasn't used the same Jet Black finish for another phone to date, but according to images shared today by leaker Mr. White, Apple tested a Jet Black iPhone X.
The iPhone X was available in a silver color that was close to white and a space gray color that was quite dark, but it was not as dark as the Jet Black color shown off in the prototype photos.
The alleged prototype device does not have an Apple logo or other certification marks, nor a finished camera design, but it is otherwise identical to an iPhone X. It's not clear if Apple will bring back the Jet Black colorway in the future, but Apple has been using a standard black color for the iPhone 11 and 12 models.
Article Link: Apple Prototyped a Jet Black iPhone X