If you want to keep the brightly colored guys ~propagate them, you'd have to graft them onto other cactus to keep them alive. You can grow regular Gymnocalycium mihanovichii on their own, if you find the green ones.

The thimble cactus you bought...were they colored as well? There's a new product out called Kosmik Kaktus. There's a post I made recently about them. Pretty colors (dyed?) but they will grow out with their normal colors. If you had a pot of these, eventually they will all be the same color. Sorry to burst your bubble.

But...there are plenty of succulents out there (this includes cactus) that are colorful (body, spines, leaves, flowers) that would make for a nice pot...IF you grouped those with like growing conditions. Good luck!

thanks for your answer! Too sad that I didnôt know this before! My thimble is not colored, I just thought it was very cute because of its shape. I planned to give color to the pot with the others :(

So the little spiked balls (seedlings??) that grow and then fall off the colored "head" are not for propagation unless I graft them?

I did create a new pot with some succulents, with only different shapes and only one red type of succulent a friend of mine was growing and I thought it was really pretty. I havenôt seen anything else with colors in the store (I go to Home Depot, of course, I am sure in more specific places I could find more interesting things).

Do you have an idea of how long will the graft be alive? If I pot it now, will I at least be able to enjoy it until the winter?

Thanks!