Technical Data
-Chemical composition
Hekla pumice belongs to the dacite group of volcanic rocks
SiO2 | 66,29% |
TiO2 | 0,58% |
Al2O3 | 15,90% |
Fe2O3 | 1,85% |
FeO | 3,26% |
MnO | 0,13% |
MgO | 0,67% |
CaO | 2,70% |
Na2O | 3,25% |
K2O | 2,27% |
P2O5 | 0,50% |
H2O+ | 1,26% |
H2O- | 0,18% |
LOI | 1,40% |
No radioactive radiation was detected in radiation tests that were carried out on Hekla pumice.
-Physical Properties
Loose dry bulk density: 0,26-0,49 kg/dm3
Depending on grainsize distribution
Loose wet bulk density: 0,54 - 0,72 kg/dm3
Depending on grainsize distribution and water content
Specific gravity of glass: 2,56
Heat conductivity: 0,07 - 0,10 kcal/m h ℃
Saturation - water, volume:
1 - 2 mm | 62% |
2 - 4 mm | 60% |
4 - 8 mm | 53% |
8 - 12 mm | 52% |
Glass and pores in 5 - 10 mm pumice, volume:
Glass | 25% |
Closed pores | 24% |
Open pores | 51% |
-Minerological Composition
The pumice is mostly glass due to the mode of formation, i.e. consolidation of molten silicates.
Only minor quantities of chrystalline material are found in the pumice. The pumice is free from clay
minerals, gypsum, sulfur and fibrous minerals. Quartz and crystobalite are not traceable by conventional
x-ray diffraction analysis.
Glass | 95,4% |
Plagioclase | 3,6% |
Pyroxene | 0,2% |
Olivine | 0,5% |
Magnetite | 0,3% |
Fragments of basalt and andesite are embedded in the pumice layers. Most of these fragments can be removed
in a washing process.