Precautions for use are useful if and only if you use mainly good quality clays.

But what is quality clay?

A good quality clay will be as pure as possible, i.e. unmixed with another type of clay and with a reduced presence or even absence of non-clay minerals, such as quartz.

A high quality clay should be 100% natural. As a mineral, clay cannot yet be labelled "AB", but who knows?

However, they can comply with the regulations for cosmetic products and obtain a Cosmebio label.

The quality of clays is extensively controlled by physico-chemical, microbiological and heavy metal analyses to ensure optimal composition.

It is still best to use clay that has been recently extracted and dried in the sun.

The type of clay to use will depend on your needs, but above all, try to check the criteria and prefer raw products to ready-made formulas, which are more likely to have been modified.

Clays, a history of colours...

Only the mineral composition, namely iron, can determine the colour of clay.

Let's take a closer look at the iron content of a material...

The state of the iron in the soil makes it possible to obtain clays of different colours.

• The more oxidised the iron (Fe3+), the more red, orange, yellow the clay...
• The less oxidised it is (Fe2+), the more the clay tends to be blue or green.

In other words, the white clay will be almost free of iron... which explains its lack of colour.

As for the purple clay, its colour is due to a high content of manganese ammonium diphosphate combined with a white clay.

In the case of the blue clay, it is the ultramarines that bind to the clay and give it its bluish colour.

Finally, pink clay is simply a mixture of red clay and white clay.

In other words, the colour of a clay is not only beautiful, but because it depends on its composition, it also affects the quality of its properties.