Period 6 element between barium and hafnium, and radium and rutherfordium, respectively. This convention is entirely a matter of aesthetics and formatting practicality; a rarely used wide-formatted periodic table inserts the lanthanide and actinide series in their proper places, as parts of the table's sixth and seventh rows (periods). Lanthanum is a chemical element with the symbol La and atomic number 57. It is the first element in the lanthanide series. It is a soft, ductile, silvery-white metal that tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It is the eponym of the lanthanide series,
Silver steel the annealed state it has a hardness of 27 HRC. It can be hardened to 64 HRC. The European/Werkstoff equivalent is 1.2210 / 115CrV3, which also includes some vanadium. Silver steel Silver steel is common tool steel that is supplied as a centerless ground round bar (with tolerances similar to that of drill bit). The name comes from the highly polished appearance of the rods; there is no silver in the alloy. Amongst other applications, it has been widely used to make such things as punches, engravers, screwdrivers. Sheffield silver steel is used in France as a blade steel for