It's a Bloomin' Lithops!

This is the largest lithops in my collection, and it's only been here for a month. I think it may be a Lithops marmorata (Edit:  Nope, it's an L. gracilidelineata!), but I'm not sure. Any opinions out there?? I have several books that include Lithops, but how experts sort them into species is quite a mystery to me- a julii can look just like a hallii, and so on! Something one needs to learn over time, or on expedition in the Great Karoo, I suppose.

It's a lovely light green, more of an Audrey Hepburn mint green than what shows in the photo.  At first it looked like it was sticking its tongue out and saying "Neener neener!", but I'm quite sure it's getting ready to bloom. Sadly, we've had no sun at all for several days, I hope the weather improves, as I think the flowers need some rays to really blossom well.

I'll call this one "Audrey" because of her lovely color, not because of the Menken musical, ha ha!