Redstone Manipulation

It's science, because it has to be. Same as our Insignia, same as the Garruw and their lightning. But I've yet to meet anyone who has a concrete reason why the weinadi can manipulate the redstone.

— Old human notation, still true

Redstone is a vibrant red stone found just below what is easily accessible on the surface. On the rare moments when is is exposed to the surface and the storms, it seems to shrink away, making its use to the garruw limited.
With some effort, the Weinadi are capable of manipulating redstone and reshaping it. It is thought that any of them can do this, but most don't because of the mental strain. In ancient times, it was believed that the Low Gods taught them this ability. Mostly this is attributed to the god Hatha, but occasionally to the lesser known god of stone, Kori.
The preparatory work towards doing this can take years, but in the right circumstances can be nigh instinctual in a matter of minutes. The preparations involve exposure to the physical redstone, especially that chunk of it which one wants to manipulate, and mentally reaching out of one's body. Some weinadi can do this instinctively, but others require special teas or a salt bath to get used to the idea.
Once the seeker can reliably achieve an out of body mental state, they can begin to control the redstone. It can become as malleable as clay in some cases, but if anyone else were to interact with it, they would still find it to be a nice hard metamorphic-type rock.
The Basadu and Yagupa primarily use this ability for decorative features, and to shift the redstone out of the way. The Dheizei have shamans who are capable of drawing the redstone to the surface, forming temporary lightning-resistant shelters. This method is considered difficult since the redstone fights to go back down, away from the storms. It does make campsite cleanup easier.