Glass is a term used to describe the effect that occurs when "shaping" graescence into a surface. Since Shapers and Shielders are rare, the term is most often used to describe graetech weapons that shape graescence into pre-defined forms. Those who carry such expensive weapons are said to be "packing glass".

Shapers are often called glass or crystal mages, though among shapers the term "glass mage" is a derogatory term used for those who are poor at shaping.

A surface is created by locking opposing gravimetric forces into a resonance. These forces interact with light, causing a small portion it to bend and reflect in such a way that the surface looks like colored glass, thus earning the moniker.

When glass is created, the light bends in such a way that makes it appear as though it is folding into shape, especially when it's formed into an edge (this is less obvious when shaping a shield). Thus, those who are creating glass are said to be "folding glass."

The color and smoothness of the "glass" reflects the quality of the surface. As the quality of glass increases, the energy necessary to maintain it decreases while the strength, durability, and sharpness of the glass increases:

• Exceedingly poor glass will have ripples in it with a light rainbow affect, indicating a misalignment in the resonance between the forces. Glass like this will take a lot of energy to maintain and the edge it forms will be less sharp than sharpened steel.
• Very poor glass will have a violet tint, created when the forces involved interact primarily with higher energy particles, bending and reflecting them. Violet glass is approximately on par with a well made steel blade. The edge is sharp, but mundane armor will deflect it easily enough.
• A surface is considered "proper glass" once it starts veering into the blue spectrum. At this point the glass is contending with the highest quality steel. While mundane armor is effective, the glass will likely do a number on it. Blue glass is the most common kind (although all glass is rare).
• Once a surface shifts into the green spectrum, it is considered superior glass. There's very little it won't cut, though it's possible for it to be stymied by thicker or rigid material. While glass is essentially frictionless, some substances will press "in" on the surface as it cuts, creating opposing force. Generally, it is advisable to only defend against green glass other glass, less you risk loosing appendages. Green glass is very rare. It is often a source of pride to own it.
• After green, the light shifts into the white spectrum. This is called crystal and is considered the pinnacle of all glass. While crystal is extremely sharp, it does no better than green glass at cutting mundane substances (which is to say: extremely well). What it is good at is defeating other glass. One would need green glass or better to successfully defend against crystal. The techniques to develop crystal weapons has been lost, however, leaving relics as the only crystal graetech left in the world... for now.
• Black glass is entirely theoretical. Any crystal graetech should be capable of creating black glass if the user were to feed an insane amount of graescence into it, strengthening the resonant forces until they form a contained event horizon. Black glass doesn't cut, it obliterates, tearing apart any matter it comes into contact with. There is no known instance of anyone creating black glass.

Generally, one can defend against glass by shielding with glass as much as one tier below. So, one can use blue glass to defend against green, so long as the gap isn't too large and the attacking glass doesn't interact with the edge of the shielding glass. This is because an edge, while sharp, is also somewhat fragile, and interacting with other glass will cause it to destabilize. This is a visible phenomenon, as glass will flicker into a lower tier when impacting other glass. For this reason, attackers will favor attacking the edge of a shield to unravel it, while defenders will attempt to make their shield as large as possible, keeping their edge out of reach.

Both shapers and graetech are classified by the kind of glass they can produce. Thus, a blue shaper can create blue glass, a green shaper can create green glass, etc. Crystal shapers would be considered the absolute best if any existed.

Just because a weapon can create a tier of glass doesn't mean a person can use it to create that glass. Even with a weapon designed for it, higher tiered glass requires exquisite control of one's graescence. It can take years for someone to learn to create blue glass, even though the weapon is perfectly capable of it. It is considered a mark of achievement to create it, something many Royals aspire to.