Strange pattern on 8670 steel after ferric chloride etch?

[Tyler.t76]

https://imgur.com/a/C3qW3gV

here’s the finished knife for anyone who wanted to see! The pattern is still a little bit visible after the stone wash the customer was dead set on haha, adds a nice touch though

 

[Stuart Davenport Knives]

Good looking knife!

 

[Alex Topfer]

i had a similar pattern in a mild steel part of a knife i did a while ago. as others said, i just assumed the mild steel was recycled and not perfectly homogenised. it's a nice subtle effect