Kaktus said:Hah... 
I am not aware of the stress issue, I thought if the cactus can survive the first week then it will be ok, I have keep her for more than 2 months, ok then, I have moved her to a less sunny spot, hope the cactus can recover soon, thanks a lot Alex.
Ive not seen sunburn yet, so its best to have kept it where it turned purple. Golden rules of cacti
-most like BAKE. Not all(epiphytes, some dwarf/grass huggers, some tropicals etc)
-they dont like to bake sudden.
-they dont like a lot of water, but also dont like to be kept dry when hot
-make sure the medium doesnt get too hot as well
-drainage drainage and drainage.
Im not sure how well aware are you but imma guess not too much.
Purple plants looks like it belong to the genus Copiapoa. But other than that I cant help you, they arent too familiar to me. Rare in wholesale, described as difficult, slow growing. Grow in the Atacama, either at the shore or on isolated pockets near the foothills of the Andes, or somewhere more uphill after that.
So where you live, it could work out for you, but dont be disappointed if it doesnt. You didnt exactly get a beginner plant.
