1/2 pound of 99.9% NanoFractalAlumina™.

These hard, high purity spherical high density alumina, which are heavier than porcelain, mill faster with negligible silica contamination. Wear and chip resistant. Easy to clean.
Features:
• Hard, tough, non-porous, chip-resistant surface
• Unaffected by most acids or alkalies
• Non-conductive, non-magnetic, resistant to mechanical and thermal shock
• Available size 4 mm
• Purity greater than 99.8% aluminum oxide
Specialty /Dispersion
Typical Nominal Chemical Composition
99.9% - Al2O3
Specific Gravity ~3.9g/cc
Available size: Nominal Size 4mm
Typical Spread (again only approximate: changes batch to batch)
Mean 3.76 mm
Standard Error 0.0225
Median 3.76 mm
Mode 3.78 mm
Porosity: Nil
Hardness: 9+ Moh
Color: Ivory
Charging Factor when used as grinding media: 9lbs/gallon