Ochre-Based and Clay-Based Sunscreens

I am currently looking for journal articles on the effectiveness of using ochre and clay minerals as a sunscreen. So far I've found one journal article that yielded positive results on the sun protection ability of iron ochre pigments, but I will try to find more data. I'm hoping there are some members of this forum who have experience making effective sunscreens from clay and ochre minerals to use while working outdoors.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136090

The only downside to ochre and clay based sunscreens is that the may be less likely to be waterproof than store-bought sunscreens. As a result they may need to be applied more frequently in humid weather compared to in dry climates.

No experience with ochre or clay but if you rub your hands on the smooth bark of an Aspen tree, this whitish silvery stuff rubs off on your hands and it can be used for sunscreen. Aspen Trees and Natural Sunscreen

May I ask why Ochre-based clay?  Would that tend to color the skin, like yellow or red?

Bentonite clay has some healing powers as it is antibacterial and anti-inflammatory.

It is my understanding that clays make good sunscreens because the skin is blocked by the properties of the clay.

Anne Miller wrote:May I ask why Ochre-based clay?  Would that tend to color the skin, like yellow or red?

Bentonite clay has some healing powers as it is antibacterial and anti-inflammatory.

It is my understanding that clays make good sunscreens because the skin is blocked by the properties of the clay.

I was interested in Ochre because I've read a lot of archeology books that mention the use of ochre in burials as well as a few documentaries me tiining the use of ochre for sun protection.

I actually happen to have some bentonite clay on hand that I gathered from a construction site. One thing to keep in mind about bentonite is that it's VERY sticky and it has a high shrinkage rate. As the clay dries on skin, it will form wide cracks in between chunks of the clay. I would probably blend the bentonite with some less expansive clay from a river bead as well as some ochre.

I make sunscreen using zinc oxide powder mixed with my homemade lotion. It works well and doesn't need to be applied very often unless we're sweating a lot. It does make your skin whiter which can be disconcerting for the delivery guy. Backwoods zombies and all....

If you want to try with clays/ochre, mix in enough olive oil or good lotion to keep the clay from cracking on your skin. The clay may still contract and dry your skin out though. I suggest trying a patch on your arm first to test for skin reaction before putting it on your face.