Technical characteristics
CHEMICAL ANALYSIS (lava powder)
| Silica | (Si 02) | 57.5 |
| Aluminum | (AL2 03) | 17.4 |
| Titanium | (expressed as Ti oxide 02) | 1.5 |
| Iron | (expressed as sesquioxyde Fe 03) | 6.75 |
| Manganese | (expressed as Mn oxide O) | 0.30 |
| Lime | (Ca O) | 4.25 |
| Magnesia | (Mg O) | 2.5 |
| Sodium | (Na2 O) | 5.2 |
| Potassium | (K2 O) | 3.00 |
| Sulfur anhydride (trioxide) | (SO3) | 0.40 |
| Phosphoric anhydride | (P2 O5) | 0.45 |
| Ignition loss at 1050 °C | 0.08 | |
For every 100 g of dry powder
Physical properties
| Color | light gray | |
| Texture | bullous | |
| Structure | alveolar | |
| Average apparent porosity | 22 % | |
| Actual porosity | 7,6 % | |
| Compression resistance (average) | 630 kg/cm2 | |
| Bending breaking point | 190 kg/cm2 | |
| Wear on metal disc | 26.6 mm | |
| Average density | 2.3 | |
| Melting temperature: 1500 degrees | 1 500 degrés | |
| Low expansion coefficient (zero at 100 °C) | ||
| Average thermal conductivity | K cal/h.m.°C = 0.42 | |