Etangen Ore

The stuff they use for the Yilneh Transport Ship hull that enhances telepathy. When the ore is refined down to a point, it can become a coating for the hull and this enhances telepathy, allowing the Yilneh to broadcast their thoughts and not have to worry about colliding with things. It even serves as an early warning system for when the Vienaran Sect shows up to throw their weight around.
This is a natural resource that can only be found on the planet of the Yilneh. The effects it gives do not replicate well and can only be refined from the ore available on the planets in the T'Vienor Expanse.
It's likely this has something to do with why the sect are so interested in the area, and why they're so bound and determined to keep it separate from the rest. Not that they know exactly what it is. They know the hulls have a particular alloy, but they haven't been able to figure out that the etangen is responsible for the difference.
It looks rather orangy in its natural state, and crumbly. In the right light, it can look like a fluffy pile of cheese powder. Shaped rocks look a bit like cheetohs, but they are still rocks and so don't eat them.
The ore is something of an open secret. All the people know this is what the folks above are looking for, so while they openly process it and use it, they don't usually mention it by name, and it would take a lot to get them to do so.

Type

Ore/Mineral