Synthetic Gemstones Uncut Cubic Zirconia Raw Material Unpolished CZ is for your jewelry fashion design.The highest quality raw cubic zirconia uncut synthetic gemstones from China manufacturer,rough stone weights are not exact and it is very heavy. Canary Yellow CZ rough stone will cut nice stones with great dispersion, its cheap and affordable rate. Man-made zirconium oxide crystal is 8.5 Mohs's scale for hardness, density is 5.65 – 5.95, refractive index is 2.088 – 2.176, dispersion is 0.058 – 0.066, heat resistance is 650°C - 700°C.