I bought two tons of Yellow Travertine Marble to get the crystal formation, a hole in a large block. I knew that in the marble industry this would be considered a difetto, (defect) but for me a tesoro (treasure).  I was able to slice 40 cm out of the larger block for a good price, the rest I'm using for legs for the unfinished TRAV PAIO.  I had made legs for this, but abandoned them as unnesessary. One of favorites, I love that I was successful in weaving the crystals into the hair.