Do you remember playdough, that colored plastic clay people let their kids play with? When I was a kid, I played with that. Then in high school art class, I played with real clay for a few weeks, and later, at the local community center, I painted a few ceramic mugs. Oh, yeah, and I've occasionally played with homemade flour clay. That's the extent of my experience with clay.
One type of Atlan in my Atlan universe is the Clay Woman, those who specialize in all aspects of clay. By the time they reach adulthood, they have learned how to sift the tiniest grains out of regular dirt and combine those grains with water to create clay. They have long ago mastered the skill of creating and firing clay plates, bowls, jars and pots. They probably have started experimenting with other shapes, such as boxes or other items that have straight sides and definite angles, instead of curves.
I admit, I tried that, too, in that high school art class. My box had five sides of different sizes, and the tops of those sides made triangles. I may be wrong, but I think the teacher fired my box all by itself, because she was uncertain whether it would blow up. Clay does that, sometimes, for a number of reasons I never fully understood. My box and its lid – yes, I made a lid for it, otherwise it was just another pot – did not blow up. However, once they were fired, the lid did not fit the box as exactly as it had as dried clay.
But a clay woman would have made a lid that perhaps did not fit the box exactly as dried clay, but did fit it once they were fired, for such an Atlan understands everything about clay. She knows how to fire her pieces for the best results, the various colors of glazes ... . In short, a clay woman knows everything there is to know about making useful items from that humblest component – clay.
Doesn't sound very exciting, does it? But despite the fact that Atlans are known as witches (what sane man would play dirty with a group of known witches?), most of their various Powers are not 'exciting'. They are specialties that make life easier for the tribe.
A clay woman has black hair, black eyes, and the heart birthmark. To an outsider, she looks like a BlackBird (warrior). If the tribe has to go to war, or at least look like it's ready for war, the Clay Women will take their places among the BlackBirds, to boost the apparent number of 'outstanding' warriors. It isn't a complete deception, because, like all the Atlans, a Clay Woman has been receiving fighting training since she first learned to walk.