to understand their physical, chemical and biological characteristics, by brightening; and illite clay, utilized for exfoliation and the constricting

Overview

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eliminating dead skin cells without causing any irritation.20 ing aqueous solution of sodium lauryl ether sulphate (1%). These were
characteristics. achieved by mechanically stirring 400 mL of 5% aqueous dispersion
attenuated in the spectral range of 400–4000 cm−1 .
Meyer.24 within the range of 290–320 nm.29 The following formula was used to
TA B L E 3 Calculation table for bulk density. 3.1 Physicochemical characteristics
= 0.91 g/cm3 = 0.9884 g/cm3 in Table 4. The pH of the analyzed clay samples was slightly acidic
out in triplicates. The constant values of EE×I are displayed in Table 1. to 5.5 clay samples in this study recorded acidic pH and they may be
plus clay soil and well as the clay soil volume as per details in Table 2. as cleansers since highly alkaline cosmetic cleansers possess a signif-
BD calculations are represented in Table 3. icant propensity to prompt skin irritation.37 They can also damage
2.3 Antimicrobial activity ranged from 4.5 to 9.5 after examining 40 clay samples that were used
positive, Gram-negative and fungal species namely, Enterococcus fae- 6.31 and those used for body beautification had mean pH ranging
Soil colour is a straightforward yet helpful indicator during soil profil- recorded oil absorption values for red and white clay, 37.41% and
ing and may contribute to the soil’s sun-screening capabilities. With the 83.63%, respectively (Table 4); indicating that the substances had a
the hue. The overall reflected light is indicated by the value of a soil ered expressive as it is reported that higher values (>20%). Red clay
tion. The concentration of colour in soil is referred to as its chroma. where they reported oil absorption values of 33 and 46% for their pink
3.1.3 Oil absorption of clay soils conducted by Silva-Valenzuela et al.42,45 The acceptable results indi-
sured plastic and apparent viscosities (Table 4) are below the minimum
were reported by Ramtekkar revealing that the smaller the particle 250 min which provides above 93% of protection. Whereas an SPF
Africa has an abundance of red soil, and this study reveals that it may Vanadium (V), 130 and 560 ppm of Chromium (Cr), 1730 and 153 ppm
have UVB-blocking characteristics. As such, it was believed that these of iron (Fe), 340 60 and 29 ppm of Zinc (Zn), respectively. Manganese
clays could be assessed for their ability to act as cosmetic products. (Mn) and Nickel (Ni) were only detected in red clay, 850 and 340 ppm,
The dry BD, commonly known as soil BD, is determined by dividing 10 ppm.58–61 For this reason, Basketter et al.61 recommended that
the weight of dry soil by the overall volume of soil. The total vol- end-user products should not contain more than 5 ppm of Cr. Both
the capacity to retain either air, water, or both.55 BD may play an avoidable limits at 130 and 560 ppm, respectively. Cr in the +III and
(Table 4). red clay had a higher content of Fe than any other metal and conse-
Table 6 lists the metals that were analyzed by XRF. Fortunately, red based clay samples (> 4300 ppm).66 Elsewhere, Thuadaji et al. recorded
(Pb), which was detected below permissible levels (200 ppm) at 27 radiation.67 However, long-term exposure to small amounts of Fe from
and 16 ppm, respectively.57 Moreover, red and white clay samples cosmetic products may cause cellular death or colorectal cancer as a
contained 119 and 159 ppm levels of Titanium (Ti), 240 and 570 of result of cumulative effects.68,69 Basketter et al. recommended that Ni,
Ti, Zn and V concentrations of about 250 ppm are sufficient to cause to the main mineral phases present, red clay is composed of major Illite
contact dermatitis in already irritated skin. Although Mn is a rare skin (56.7%) components with admixtures of Quartz (31.3%), albite (9.9%)
sensitizer, there are reported cases of increased menstrual blood loss and minor amounts of Vermiculite (2.0%). The white clay was found to
and pain as a result of repeated exposure.61,70 contain Illite (34.5%), Albite (33.8%), and Montmorillonite (31.7%). A
from both samples at detectable levels because prolonged exposure to of Quartz (31.3%). According to Khiari et al, a Quartz content above
these substances at high radiation levels can result in acute health con- 15% is cause for concern, even for topical applications, as there is suf-
limit of 200 ppm.71 This indicates that these two radioactive elements Illites containing even higher amounts of Fe have been reported.73–75
sitions consequential from XRD data are shown in Table 7. According up waxy and sticky substances from the skin and they might even be
sus various microbial species are presented in Table 8. The results a panel of bacteria and fungi, including E. coli and Candida albicans.80
drinking water. Adv Mater Sci Eng. 2011;2011:872531. https://doi.org. Kaye and Laby tables of physical and chemical constants. Archived

Methods (brief)

S’busiso Nkosi, Technology Station in was to characterize two different samples of red and white clays for their physical,
draw excess oil and impurities from the skin. On the other hand, smec- ity of the clay soil samples. 2 g of the clay soil sample was added in
poses by the Zulu and Xhosa communities. In this study, the potency of The clay soil samples’ plastic viscosity and apparent viscosity were
sample at 14,000 rpm for 30 min.28
The red and white clay samples were harvested from uMzinyathi, 29◦ tube as the excitation source and a silicon drift detector.
30′ 0″ South, 30◦ 56′ 0″ East in KZN (Northern part of Durban) were Scanning electron microscopy (SEM)—The samples were dispersed
for them to be transported. The samples were brought to the lab and morphology.
2.2 Physical and chemical analysis cuvette. 1 g of the soil sample was measured, then transferred into
Colour determination was done by aerating raw samples for 24 h and mixed with the shaker for 10 min, and filtered through Whatman filter
paring the samples visually to the standard soil colours shown in the using ethanol. After that, a 25 mL volumetric flask was filled to the top
Samples of clay were tested for pH using a portable pH meter ethanol as a blank, the spectral absorption of samples in solution was
The oil absorption was determined following the American Society determine the SPF of the clay samples and the control material:30
for Testing and Materials methods.25 A 10 g sample of clay was put on
layer of oil by slithering the spatula over the top surface of the formed In this case, the absorption of the diluted sample is represented by
TA B L E 2 Bulk density masses and volumes of soil sample. ples. The disks with antibiotics and filter paper disks infused with red
and white clay samples were positioned on the surface of the Meuller
cylinder (g) sample (g) soil (mL) the soil (g)
both antibiotics and clay samples zones were read to establish whether

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The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised