GC Initial® LiSi Press additional shades. A revolutionary new lthium disilicate pressable ceramic, it combines unparallel strength and amazing aesthetics. Best of all, it is fast with processing, optimized to be used with GC Initial® LiSi Veneering Ceramic and leaves virtually no reaction layer making your laboratory more productive. GC Initial LiSi Press pressable ceramic. (Lithium disilicate ingots for the pressing technique). Same as existing GC Initial LiSi Press ingots. This is a shade line extension.