Phantom Adamantine Effect

A phenomenon which typically occurs in noble metals. At a high enough magical charge, the light substructures essentially form a phantom adamantine construct within the metal, which then eats through the other material just like any other hard light construct does before winking out. This also has to do with some rather famous relics where swords and such are embedded into stones: any ordinary blade would shatter, but one charged enough to create this light effect would essentially be temporarily invulnerable.   Because hard light/adamantine is a perfect insulator, all affected materials also become better thermal insulators as their charge increases.  

In motion

Interestingly, the fact that these materials reinforce themselves with hard light can result in some odd interactions when highly charged and moving at great speed. The classic example of this is embergilt swords being reported to cut through heavy iron, and even steel. These may be taken as exaggerations at first, since a sword edge really just physically can't cleave through thick plate armor no matter how sharp it is due to limitations of human strength and material hardness/density, but there is actually some truth to it. While exceedingly rare in the case of swords, the entire design of the embergilt scythe was built around the capability to pierce through another noble's armor at its strongest points.   Infused noble metals act almost like highly specialized mage implements in the way that they convert input magical energy into a tangible hard light effect. So when a blade of say, embergilt, is being channeled into by a wielder, they're essentially casting a projection of the sword inside the sword. What this does is allow the metal to utilize hard light physics to a limited degree: the principle that hard light is completely unaffected by non-internal forces, drawing from the energy source to make up the difference. It does this more efficiently than most projections, but to a more limited magnitude of effect. The result of this is being capable of cutting through iron plate with embergilt, should one's will be great enough.   Perhaps more importantly, this effect also dramatically reduces the chance that a moving object glances off another: the nature of hard light grants the strike an additional degree of momentum, preventing it from deflecting off course. This comes into play with sharp objects and armor.  

'Lightness'

An odd side-effect of this phenomenon is that it reduces the effect of gravity on objects- highly charged noble metal infusions, for example, will fall at measurably slower rates despite having the same mass. This is a result of the adamantine resisting incoming forces, including gravity. Meanwhile, this effect inverts for anything sharing the object's claim (most typically, any coherent soul claiming the object and fueling it with their Will), making it easier for them to move than the mass would suggest.