Properties of Batubara lan Pumice
ukuran gandum
medium kanggo nggoleki coarse grained
grained nggoleki
tilas
ireng
putih, greenish putih utawa abu-abu
porosity
kurang keropos
Highly keropos
luster
kurang kanggo vitreous kanggo submetallic
earthy
kekuatan compressive
ora Sumadhiya
cleavage
non-ana
sampurna
kateguhan
ora kasedhiya
3
tartamtu gravitasi
1.1-1.4
2.86
Kapadhetan
1100-1400 g / cm 3
0.25-0.3 g / cm 3
resistance
tahan panas
impact tahan, meksa tahan