... %,Y2O3 5.2+/-0.2% Good round sphere,smooth surface,pearl-like sheen. Zirconium Oxide Bead Specifications:Composition:ZrO2 94.6%,Y2O3 ... /cm3 Hardness:HRA> 87Hardness on Moh's scale:9Characteristic:Good round sphere, smooth surface, pearl-like sheen.Good tenacity, impact-endurable ... under high speed impact.30-50 times better than glass bead in terms of wearability.Higher density than any other grinding ...