Thank you from wayyy across the pond
@syzone8aUK! And thank you
@Daisyl and
@madcratebuilder for the information. I actually had one of those Gymnocalycium before, same setup but it was red. It shriveled and died and I could not figure out what I had done wrong. Now I get it. I am having trouble (and will Google) understanding how the Gymnocalycium existed and survived on its own before man came along and decided to graft it to something. Cactus plants are pretty amazing and I always scoop them up when they are on clearance just so I can try to get better at growing them.
I have cut up my Chroma and yes, I have 10 new plants to baby along! I used to think gardening was fun, but seriously I am getting mad-scientist-like over propagation and seed collecting.