A corrupted Lissant is a large mineral that has started to appear shortly after the meteor impact, they appear much like an ordinary Lissant crystal with a violet or reddish hue that grows gradually darker the longer they remain active. Additionally, their size can be significantly greater and it is presently unknown if there is indeed an upper limit to this due to their recent appearance.
Generally, a corrupted Lissant has three stages it will go through before 'maturing'.
Stage 1 - The Lissant will begin to change colouration with a red or purple hue appearing beneath the surface, this has a veiny appearance and will gradually spread over several weeks.
Stage 2 - The Lissant has changed colour from a blue hue to violet or crimson and cracks will begin to form across the surface when this happens, Myst will begin leaking out into the surrounding area. This isn't significant enough to have an impact on the local environment but will slowly begin to proliferate Mysts. If part of larger deposit veins below the surface may begin 'corrupting' other nearby Lissants and exhibits features similar to a viral infection.
Stage 3 - Additional growths will begin to appear across the crystal giving it a chaotic shape, with each functional becoming a multiplier causing Myst proliferation to increase rapidly. At this stage, the Lissant is unstable causing it to generate an electrical field that will strike out against anything that comes within the 20ft. Spells cast at it have a habit of going 'wild' causing them to become significantly stronger, weaker, or produce an unintended effect.
Left unattended, it will also begin to expose local fauna and flora to the Mysts, possibly causing mutations or making areas of land uninhabitable. Prolonged exposure with the Lissant at this stage for prolonged periods is very likely to cause death, although some report seeing creatures with similar crystal-like growths.
Thankfully the removal of such crystals is made relatively easy providing one can safely approach them, being made extremely fragile and brittle by the cracks it is usually possible to destroy them with blunt force. However, it is recommended this task is accomplished from the range typically using siege equipment (Onager or Trebuchet).
In theory, these crystals could be used to enhance magic, but doing so exposes the caster to the dangers of wild magic, and it is possible for spells to backfire, damaging or wounding unprepared individuals. If used this way there is a 50% Chance of the effect occurring.
Corrupted Lissants are a recent development and not much is known about the processes or causes that have led to this development. However, most experts believe the sudden discharge of Myst caused by the impact may have overwhelmed or damaged or exposed some impurities in the crystals to develop cancerous growths.
Presently there are several regions known to have been affected by the phenomenon including but not limited to Kriege, Lantherni Wilds, and the Tor Molosva spine.