Purifiers and Glassing, or Global Planetary Annhilation

Simply referred to as Glassing, this is when the fleets of the Shraadus Empire unite and reshape their ships into forms designed to totally obliterate the surface of planets in order to "purify" threats to be considered highly dangerous, such as freelancezero's infamous Nightmare Plaque from consuming and reproducing on worlds. This is done in a few ways, the main one being,

STEP 1: The designated area, (50-100 mile diameter circle, depending on geography and environment), is placed with 1 or more 50 megaton Nuclear Warheads,
STEP 2: 5-10 Purifier CCS Cruisers, and 1-3 of the remodified purifier Super Carriers are given target locations in the area of the Nuclear Blast to aim with.
STEP 3: Each will charge its underside Plasma Lancer, an energy weapon that shoots a beam of Plasma at the surface of the planet.
STEP 4: Release, repeat.

The significance of the Plasma Lancer is that, when the beam strikes the surface, the magnetic field guiding the beam collapses, and based on how powerful the energy release was, is similar somewhat to a nuclear detonation, on a different scale. The initial impact zone of the beam is instantaneously obliterated, while the areas outside of the initial impact zone are affected by the heat wave generated by the blast; depending on the range, those closest outside of the blast zone are instantly killed by the intense heat As thermal expansion takes over, the resulting flames fan out and create a pyroclastic surge, which will continue to burn the areas it comes into contact with until it has cooled enough that it cannot harm the surface.
Subsequently, the atmosphere is saturated with soot and ash thrown up from the initial impact, subjecting the planet to a kind of nuclear winter. As the initial impact area cools, the surface is covered by extensive areas of molten soil, and is comparable to active volcanic sites in some parts of the world, on a larger scale depending on the extent. The destructive process leaves the planet unable to recover to its former state. As a result of the destruction, the atmospheres of most planets have been known to boil away in the process.

The rocks, soil and dirt become turned into a mineral called lechatelierite, which is a glassy like substance, hence the name.


The first picture is an example of high-altitude glassing, to give you a good look on the target area and its effects.
The second picture shows you is what would be considered low-altitude glassing, to give you a good look on how this affects cities or other civilian population centers, which are usually intended targets.







and yes, i got the pictures and most of the paragraph from halo wiki.