**2. Base Materials of Geopolymers**

#### *2.1. Mineral Precursors*

As a geopolymer precursor, any aluminosilicate that is able to dissolve in an alkaline solution is suitable. There is a wide range of reactive products that can be used, including calcined or non-calcined clays [12], industrial or agricultural by-products [13] and artificial pozzolans [14]. However, the choice of raw material may depend on several factors, including availability, cost, and type of application. The raw materials may be distinguished as primary and secondary raw materials.

#### 2.1.1. Primary Raw Materials

According to the literature, Geopolymer production can be achieved using raw materials with high silica and alumina content. The main sources of primary raw materials are natural minerals. [15].
