Lithops, the original fake stones; or, as they are known in the horticultural world by their common name 'Living Stones' a genus of succulent plants in the ice plant family, Aizoaceae a Mesembryanthemum species. A sizable variety of these are found in southern Africa. See these links for some images and videos of them:
http://en.wikipedia.org/wiki/Lithops ,
http://www.travel-tour-guide.com/Namaqualand_flowers_photos_south_africa_succulents_trip/07_lithops_photos_conophytum_photos_fenestraria.htm , and
http://www.youtube.com/watch?v=4d-6sKc23YA .
During the '60s and '70s I collected these plants for awhile and added them to my cactus collection - a fun hobby. While creating this image using dandelO's streamlined stones clip file, I had thoughts that if made small enough, the fake stones might look enough like Lithops that I would titled the image appropriately.
Elements used for the image include: Dune's heather plants and Walli's Dry Grasses including his ND Grasses available at NWDA. Note:
Walli, these Lithop plants might make a great model addition to your collection especially if created in clumps for populating. The terrain was created with TG3 and augmented with glen5700's Voronoi fractalized file, Hetzen's flatten low areas file; and, dandelO's 1m cracks file.
In all, I was pleased with the outcome ...enjoy.