Grade A, called Cathedral Cut, is grown slowly from high-purity morrow. It is reserved for city-scale wards and surgical-level sigils. Efficiency is essentially five out of five. The risk profile is low, but the cost is severe; almost no waste, almost no drift, and casters report the cleanest, narrowest lacunae.
Grade B, known as Bonewhite, is the standard refine. It powers lamps and field wards and behaves predictably. Efficiency is four out of five. Costs are steady and well-mapped; most trained casters can plan their lacunae with Bonewhite and keep anchors intact.
Grade C, or Ash-Glass, comes from mixed lots and "rainy batch" runs. It is used for training and small tools when precision is not everything. Efficiency is three out of five. Burns are noisier and the side effects wander; anchors must be checked afterward.
Grade D, sometimes called Street Blend, is a scrap mix. It mostly feeds common lamps or decoys. Efficiency is two out of five. Expect anchor drift, a dirty aftertaste in the mind, and larger-than-predicted lacunae if you push it beyond trivial effects.
Grade X is quickglass, an illicit living charge. It hits as hard as or harder than Cathedral Cut, often beyond five out of five, but the price is catastrophic. Lacunae are violent, personality shear is common, and repeated use leads toward overhollowing. It is a crime for good reason.
The working economy of a burn is simple to say and hard to live with. The scale of an effect is roughly equal to the milligrams of grain you burn multiplied by the purity factor of the glass, then reduced by all the waste you introduce—sloppy vectors, tired hands, bad breath control, panic. Waste shows up as heat in the body and smear in the mind; both increase the spread of the lacuna. The colder you keep the body and the cleaner you keep the vector, the smaller the hole you carve out of yourself.
A practical rule of thumb: if you must mentally calculate the burn mid-cast, you waited too long to plan it. Measure the grain, decide the vector, touch your anchor, breathe once for the body and once for the word you're about to speak. Then burn. If the room is hot or the glass is dirty, halve your ambition. You can always cast again; you cannot easily stitch back what you hollowed.
Example for field use: a Lumen flare with two milligrams of Grade B and the wrist sigil paired to the phrase "Burn bright, not me" will clear a ten-pace circle for a few breaths. Most casters report a brief flattening of warmth afterward that fades within minutes. Push the dose or downgrade the purity and the light widens, but so does the numbness that follows.