Grain Size
Large and Coarse Grained
Medium to Fine Coarse Grained
Fracture
Not Available
Conchoidal
Porosity
Less Porous
Highly Porous
Luster
Dull to Grainy with Sporadic parts Pearly and Vitreous
Dull to Vitreous to Submetallic
Compressive Strength
Not Available
Cleavage
Not Available
Non-Existent
Toughness
Not Available
Not Available
Specific Gravity
2.6-2.7
1.1-1.4
Transparency
Opaque
Opaque
Density
2.6-2.8 g/cm3
800-801 g/cm3
Resistance
Heat Resistant, Wear Resistant
Heat Resistant