Desert gems

I saw these at the garden center at Walmart for the first time today. Dyed cactuses.  These are so cool. They inject them with dye the same way they make those "blue" orchids.  Of course the spines will shed and new ones will come in the normal color so this is not permanent.  But so cool.  Very tempting to buy. I love the green and purple ones but I know they won't stay this way so no need to spend. I couldn't find a price. They must have just been put out.