The darker purple crystal will be tweaked again to better fill the role of a black crystal.
Like Rimmer said
Yes, item ID's are currently a finite resource. We're hardly scraping the barrel, but it is something we have to consider when adding blocks.
I'm a huge fan of decorative things, so i'm not opposed to the idea at all, but the intended role of these crystals are not purely decorative. I can't give a yes/ no to this currently unfortunately!
Really? You'd rather have less than you could, simply because you can't have everything?