| http://www.w3.org/ns/prov#value | - at least a factor of 1.5, 2, 2.5, or even at least 3 as compared to a comparative glass-ceramic made by heat-treating, in the same manner, the same glass free of Nb2O5 and Ta2O5 (i.e., the comparative glass is made and heat-treated the same manner as the glass comprising the Al2O3, REO, at least one of ZrO2 or HfO2, and Nb2O5 and/or Ta2O5 except no Nb2O5 or Ta2O5 was used to make the glass (i.e.,
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