Quoted from madtown:pretty sure all of this "HD" glass is simply low iron glass...very common in the aquarium trade...you can get 3/16" thick glass cut to any size you want with sanded edges...i just checked $139 shipped to my door...type "starfire glass" on google...no need to pay over $200
No indication that the Starphire glass has the anti-reflective coatings or properties of the three premium products being discussed here.