I have a nice black silkie roo at auction right now, not split to anything as far as I can tell.
https://www.backyardchickens.com/forum/viewtopic.php?id=588919
I am not NPIP
Here is a black girl, struck an amazing pose the other day JUST when my camera was pointed at her, charged, room on the card, and light enough outside, no one in front of her, contrasty background. She doesn't always look this good, just the other day.
Ditto on the "really dark blue" thing. There are silkies that have "off black down" and sort of a sooty black flight feathes but mostly "blackish" plumage, but they produce blue. If you are looking for a black rooster, and want to be SURE you are not getting blue, I would look for one with black...