... construction, normally because of the different Country of Origin with the different types and quantity of impurities, resulting in ... brown and other colors, hardness 7.8, specific gravity 4.6-4.71, 1.93-2.01 refractive index, birefringence, absorb light directly ... oxychloride, zirconium, sodium fluorozirconate, potassium, zirconium sulfate, etc.). 2012 HOT SELL zirconium sand with good quality