Glass fibres for reinforcing organic and/or inorganic materials

The invention involves a reinforced glass fiber, expressed by weight, consisting of the following components with the following content in: SiO2:58%-62%;Al2O3:10%-16%;CaO: more than 18%;MgO: more than 1.5%;CaO+MgO: less than 28%;Na2O+K2O+Li2O: less than 2%;TiO2: less than 1.5%;Fe2O3: less than 0.5%;B2O3: less than 2%;F2: less than 2% ; The portfolio also contains other components is less than 1%, F2, B2O3, and Li2O and components, at least one of the three content greater than 0.5%. This fabric costs and to get a good balance between fiber-forming properties.