My Black pearls were as the pics above show-the difference in green leaf color.
But I think my original plants were a more red/purple.
Only the new growth was semi green/purple on the Pearls.
Black prince could be almost all purple/green in Southern exposure-TONS of hours of sun.
Still had green leaves with purple tones at most unless in direct sun.
Then dark green with purple.
Pods on both are different in shape and black prince doesn't cluster the sane(tighter plant).
IF I remember right,Black pearl was a LOT tighter/compact plant too, no matter the size.
Pods were tighter together too.
Prince was more like a common type ornamental.Lots of pods distributed but not in tight clusters.
There are also several varieties that are called or sold as whatever by vendors.
Check out Black Prince,Black Pearl,Black Namaqualana,Black Manaquelana,Black Cuban,Black Cluster and a few more.
Vendors can sell a lot of these as another pepper.
See how vendors sell the same thing under different names,even though the seeds might be from the same plant.
Re naming stuff is very common these days.
With super hots especially.
Anything in demand or new names makes $.
Not that EVERYONE does it.
Just whatever people buy as a new whatever sells.