Hard Light

Hard light, fundamentally, can be thought of as the 3D 'shadow' of a Celestial body. This also happens to be why it is utterly immutable.
Uses blue quanta to create constructs that only exist as long as the magic is fed into them. Human-generated hard light naturally has an element of green quanta for shaping purposes. Notoriously energy-intensive since there is no dimensional assistance, and efficiency heavily depends on how well a person is able to conceptualize the object that they are materializing. It is the basis of arcane magic, being useful to create perfect forms: airtight enclosures, extremely thin blades, perfectly straight corners.

Behavior

Hard light isn't even strictly a material, and as a result, doesn't really follow conventional physics. Being an entirely magical effect, hard light is bound by the Magical Coherency Limit, meaning that infinitesimally thin projections are impossible.

To its creator, it is massless, taking zero energy to move. To everything else, it's a completely immovable, perfectly rigid object. Every instance of hard light has a pool of energy from which it draws to counteract incoming forces: once this is expended, the hard light construct disappears. The exact efficiency at which different forces are nullified varies.

The energy it requires to materialize a projection (instantly drawn from the new projection's pool) is proportional to the energy required to displace what currently exists at that position. Even with a perfectly efficient projection method, energy would still be expended displacing air.
Hard light on hard light collision causes the weaker hard light to instantly wink out. Hard light weapon projections are generally built in layers to counteract this. Adamantine on adamantine, depending on its exact structure, either cold welds or slides with zero friction.
Moving a hard light construct consumes some of its energy, even in a vacuum where there's no air to displace. As the speed of a projection increases, its energy consumption grows at an exponential rate- as they move faster, they consume a lot more energy.