They are mostly not as dark as Limania's. I have some dark ones growing and even they have a green one in the middle of them. If you pay a lot of money for the seed and they come up pale colours or green then you may be disappointed.
I have found that they are not too difficult here but I do give them a little less water than some Lithops.
If you try them let us Know how you get on.
Lithops,Cacti,Conophytums,Tylecodons,Sempervivums and Sedums