Lalique has seven Meilleurs Ouvriers de France (best workers in France) on its staff. Registered in the glassmaking-crystallising class, they are engravers, sculptors, cutters, or glassblowers. A regular blow creates a glass bubble at the end of a hollow cane. The glassblower must obtain a smooth surface and remove any imperfections (such as bubbles) with a blowtorch or by hand. Lalique reserves the mouth-blown technique for round crystal objects (vases, bowls, etc.). It is the lead oxide (24% minimum and 30% for the upper crystal) that gives the crystal its malleability and brilliance.