GC Initial Zr-FS Gingival Universal GU Gum GC Initial Zr-FS is a porcelain that is specially adapted to the zirconia skeleton. The porcelain has a high content of feldspar, which provides good aesthetics and a stable porcelain that does not need long cooling phases. GC Initial Zr-FS has the same color system and layering technique as the other modules in the Initial system Physical data: CTE 9.4 x 10? 6K? ¹ (25-500 ° C); burning temperature 810 ° C (1st dentin burning); glass transformation 550 ° C; flexibility strength 90 N / mm²; density 2.43 g / cm³; solubility 12 µg / cm²; medium particle size 21.5 µm.