1) Extraordinary hardness
2) Measures: 2-4cm 6cm ,6-8cm ,8-10cm ,10-12cm ,12-15cm.
3) High content of silica
4) Good money
Silex blocks are extracted from a very extensive area of mountains whose detachment was swept away by rivers, seas, etc. Formed so that boulders which also extract and selected by measures for grinding pastes, ceramic raw materials and derivatives.
Silica: SiO2 98,7 Potassium Oxide: K2O 0.19
Aluminum: Al2O3 0,21 Titanium Oxide: TiO2 0,26
Iron Oxide: Fe2O3 0.24 Magnesium MgO 0,04
Loss on Ignition (1000 ° C) 0.15 Cal: CaO <0.01
Actual density 2,65 Mohs Hardness 8 Total resistance to acids, salts, bases ... with the exception of hydrofluoric acid and its compounds.