When my husband built his back in September, we were looking specifically for the black crystal but unfortunately, according to the CM, they had to stop mixing in special crystals during the experience since there was usually only one of that type and it was unfair to other guests who didn't pick first because they missed out. I'm not saying that's the truth but it's what we heard from the CM. They did say that occasionally you can find the other crystals in the other shops around Batuu!