The gracilidelineata flower bud is growing quickly. It's really pushing it out now.
I first noticed it on the 21st and yesterday, on the 24th, the flower bud looked like this:
Lithops gracilidelineata flower bud close up on August 24, 2012
Lithops gracilidelineata with flower bud on August 24, 2012
I think it's going to be a yellow flower. As far as I remember gracilidelineata all have yellow flowers. And the slightly yellow tip of the flower bud also seems indicative of that.