Use of a clay in the preparation of a geopolymer precursor

A method for preparing a geopolymer precursor comprising the following steps:

• providing a clay comprising:
• less than 30% of kaolinite;
• at least 20% of at least one of muscovite and illite;
• and
• from 1% to 20% of smectite;
• a weight ratio of the at least one of muscovite and illite to the kaolinite being greater than 1;
• optionally drying the clay;
• optionally milling the clay;
• calcining the clay at a temperature between 650° C. and 900° C.;
• and
• optionally deagglomerating the calcined clay until reaching a median diameter from 10 μm to 20 μm.