Large chunks of tempered fire glass reflect more light than small chunks of fire glass.  With more surface area to reflect off of, 1/2 inch Cobalt fire glass is perfect option for both stainless steel fire pits and Cor-ten steel fire pits.  With the flames of your natural gas or propane fire pit turn on, flames will emerge between the larger pieces of glass and create a sparkling glow.   Also consider a combination of Cobalt and Clear fire glass.  This combination is sure to impress your family and friends.