Yliaster is an alchemical metal used primarily in the construction of mêlée weapons. Yliaster is more reflective than most normal metals, even in semi-worked state; it holds an edge or an even surface very well.
When a blade made of Yliaster is held in hand, and the wielder is ready to fight, it seems like the blade gains a glow. The colour of the glow varies with the exact alchemical construction of the blade (greenish, purple, white, red and yellow are common, but trends and popularity of variations change over time).
When the first alchemist forged an Yliaster blade, he thought that it would make the user easier to notice. However, it turned out that the glow is not visible in darkness. Furthermore, it cannot be recorded on video or a photo. Modern cinematographers are forced to ask SFX teams to add the glow when featuring such blades in the action.
When wielded by a focused, sapient mind, blades made of Yliaster gain an armour divisor of (10), deal an extra +1d of damage, and not only pass through Orgone Shields, but also deplete the shields they pass through at the same time. Yliaster blades cost 10 times as much as normal ones (+9CF), but with a total final cost no lower than $500, and are considered Very Fine (Materials) for breakage purposes. They can still also be made Fine (Balanced) and/or Ornamental.
The peculiar benefits rely heavily on the metaphysics of this material. Neither the armour divisor nor the bonus damage apply when cutting into a flat or otherwise non-convex surface. Thus, it works just fine for cutting down medium-sized trees, chopping wheels in half, or cutting off a small turret from its base, but it's no better than a regular knife when trying to make a hole in a door, chop through a side of tank armour or use it as a digging aid.