A review that brick can act as geochemical indicator of soil. Reference: Elemental and trace elements characterization

The elemental and trace element characterization of the fired clay bricks of monuments and soil of the surrounding area showed the high wt. % of SiO₂ (~ 71 % _Brick-78 % _Soil), Al₂O₃ (~ 14 % _Brick - 10 % _Soil), and Fe₂O₃ (~ 4 % _Brick - 6% _Soil) with low wt. % of Na₂O (~ 1%), K₂O (~ 1%), MgO (~ 2 % _Brick - 1 % _Soil), CaO (~ 1%), etc. The raw materials of brick are siliceous and Ca-poor; the same nature is shown by the soils of surrounding area. In both brick and soil samples, the high percentage of non-metal and transition metals among different families of trace elements indicates geogenic similarity among their sources. The result indicates that brick can act as a geochemical indicator of the soil. The results also indicate that the local community was involved in the production of the bricks and the construction of the monumental structures.