Frailing

First it frails and then it fails.
~ Calgras, Glass Inspector

Commonly known as "Glass blight" or "Mirror pest" Frailing is a strange phenomenon that affects nearly all types of alchemical glasses and gradually weakens their internal structure to the point that they either break under their own weight or due to external pressure.
While such a disease would be little more than a mild annoyance in most cities of Cenorad, it is nothing short of an apocalyptic threat within the Shimmering Metropolises of the Vitreous Empire, given the fact that they are nearly entirely constructed from alchemical glass.

Transmission & Vectors

Frailing can be transmitted from one piece of glass to another via physical contact, with the risk of an infection becoming higher and higher the longer the two pieces stay in contact.
Particular intense forms of contact such as rubbing or grinding further amplify the chance for an infection, which makes the highly stressed glass parts of numerous alchemical machines especially susceptible to contract Frailing.
Additionally, there is also an increasing number of observations, which seems to indicate that Frailing is able to spontaneously appear within a piece of glass, which -if proven true- would crush any attempts to ever fully contain this threat.

Causes

While it is currently unknown as to what exactly causes, there are a great number of theories, which attempt to give an explanation for this phenomenon.
One of the most common theories assumes that Frailing is caused by errors or mishaps in the production process of the glass, such as incorrect mixing ratios of the raw materials, inaccurate transmutations events or accidental contaminations with unwanted materials.
Other theories believe Frailing to be caused by cross-reactions of the glass with the various air- or waterborne pollutants emitted by the vast industrial complexes that cover ost of the Metropolises' area, though, given the fact that glass which has never been exposed to the factories exhausts, can also be affected by Frailing it is doubtful that these pollutants are the sole reason behind this phenomenon.
A small number of Educated scholars, who possess the necessary clearance to know about them, suspect that the Muli'he are ones responsible for the frailing of alchemical glasses.

Symptoms

Shortly after the infection, the affected piece of glass will begin to gradually lose its coloration as well as any reflective properties, starting with a roughly fingernail-sized spot located somewhere on its surface.
Once this so-called "Dull Spot" has become fully opaque it will begin slowly to expand until it is either removed or has encompassed the entire surface of the afflicted glass. While the expansion of the Dull Spot is ongoing the glass that has already been transformed by it, will begin to thin and additionally become far more brittle than uninfected glass.
These two factors together make the transformed glass far highly susceptible to crack and subsequently shatter under the influence of externally applied forces, which can have potentially catastrophic consequences if the affected area is, for example, a load-bearing part of a supporting pillar.

Treatment

The so far only "treatment" for Frailing is to liberally cut out the affected area and isolate the infected glass piece in order to prevent it from coming into contact with other glass products. Once the glass piece has been successfully isolated is has to remain securely locked in a non-glassy container for an extended amount of time until it has been fully reduced to a non-infectious glass powder.
Because of this, it is vitally important to frequently and regularly check all glass surfaces for signs of Frailing, in order to prevent the disease from endangering the structural integrity of an entire building.

Prevention

Given that Frailing only affects alchemical glass, especially vital structures can be reinforced with non-glass materials such as wood, metal or stone to mitigate the riks of a frailing related collapse.
The same materials can also be used to create dividing strips within a glass structure in order to prevent the Frailling from spreading throughout the entire structure.

Type

Nanite / Mechanical

Origin

Magical

Rarity

Uncommon

Search. Cut. Prevent.

The so-called "Frailing Department" is a sizable organization directly subordinate to the Mirror Ministerium that is tasked with the search, removal and subsequent storage of frailing glass pieces.
Given the fact that nearly every item larger than a simply marble created within the Empire is made almost entirely from alchemical glass, the members of the department are perhaps some of the busiest persons in all of Cenorad.

Frail Safe

Thanks to the little adjustments I made to the glass formula, it should no longer be frailing.
Though you want to keep it away from sunlight and water or things might get...interesting.
~ Lord Zissil, Alchemist of the Saphire Guild

While a great amount of effort was put into the development of "Frail Safe" glasses, the results of these endeavors are unsatisfactory, to say the least.
While some Alchemists were able to create new types of glasses that were either immune or highly resistant to frailing, they all possess their very own flaws and drawbacks that severely hinder their large-scale use.