## 3 Results and Discussion  
The studied geophagic samples RW and RR, prepared in mines, presented whitish and reddish colors (Table 1), which are associated with geological processes from which the mine materials originated (sediments of coastal dunes (whitish) and continental dunes (reddish) eolian origin). According to previous studies, reddish and yellowish materials are probably enriched in iron oxides and have been the most preferred by consumers in Swaziland and South Africa [47]. Samples sold in Maputo markets presented three color categories: the MXR, MZR, and MER market samples showed a reddish color, and MZW and MZY samples were whitish and yellowish, respectively. Whitish materials suggest a link to clay minerals [48]. Yellowish samples found in the Zimpeto market may have an origin in different mines or be the result of a mixture of whitish and reddish geophagic materials and/or other additives. Supplement additives to geophagic materials are a common practice in many African markets to provide multiple choices for consumers [49]. Samples MZR, MER, and MXR revealed a slightly acidic pH (6.09 to 6.17), samples MIW, MIR, RR, and MZW presented a neutral pH, ranging from 6.98 to 7.18, while samples RW and MZY showed a slightly alkaline pH of 7.52 and 7.51, respectively. The reddish-colored samples from the markets showed a tendency to acidity. Ref. [50] reported that acidic geophagic materials are more preferred by pregnant women in Kenya, Malawi, South Africa, and Nigeria. The preference for acidic materials is traditionally accepted as capable of preventing excess saliva secretion and reducing nausea during pregnancy [51, 52]. According to [53] slightly acidic geophagic materials aid in gastric juice neutralization. Electrical Conductivity (EC) showed a clear distinction between unprepared (13 and 25 \(\upmu\)S/cm) and prepared in mines (28 and 47 \(\upmu\)S/cm) materials and samples from markets (264-465 \(\upmu\)S/cm). The slight EC difference between unprepared and prepared near the mine samples may be associated with sieving once fine fractions are more conductive [54], while higher EC results in market samples may be the result of additives (e.g., NaCl) added to geophagic materials, to improve flavor. Other studies reported high EC values in geophagic materials with salt added, and that can be linked to diarrhea-causing enterotoxins absorption and to gastrointestinal epithelium protection [55]. Unprepared samples MIR and MIW showed similar OM content. Prepared sample MIV had the higher OM content (8.14%) of all samples, suggesting additives. OM-rich geophagic materials are likely to have more bacteria added, some of which can be pathogens, including _E. coli_, _E. histolytica S. typhi_, and intestinal helminth infections such as _A. lumbricoides_, _T. trichiura_, and _S. stercoralis_[47]. Materials sold in markets OM ranged from 1.21 to 2.76%, similar to other studied geophagic materials, e.g., in Zaire, Thailand, and Uganda, 0.2 to 1.5% [51]; Cameroon, 2.32 and 3.02% [56]; and South Africa and Swaziland, <1.7% [47], which is considered with a low risk of bacterial aggregation. Textural analysis of studied samples revealed that sand-size particles are the most representative (Figure 4). Unprepared mine sample MIW is the one with higher sand content (93.02%), while samples MER and MXR presented lower sand content, with 57.02 and 61.34%, respectively. As expected, samples with higher clay content were the ones prepared for geophagic consumption. The prevalence of sand fraction in prepared samples contradicts the belief that soils deliberately ingested are of clayey texture. The same sandy trend was reported in South Africa, Swaziland, and the Democratic Republic of Congo [57]. Silt fraction granulometric distribution revealed that clay size presented the higher content (67.5 to 88.1%), except in sample MIW (27.9%), which is ranked MXR > MZR > MER > MIR > MZW > RR > MZY > RW > MIW (Figure 5).