In my usual daily obsessive compulsive searches across the internet for all things lumia related I came across a NIST publication that lead me down a couple rabbit holes.

Fractography of Ceramic and Glass
https://nvlpubs.nist.gov/nistpubs/sp...p.960-16e2.pdf

This goes a long way towards describing "some" of the more desirable effects that we note when torturing glass for lumia. Quantifying these characteristics I thought would go a long way towards generating a richer dialect for this topic.

I mean, how do you describe the internal structure of bent glass?! How might one purposely load and fracture a material to achieve certain optical properties repeatably and reliably?
This publication helps I believe.

Most interesting, I thought were the generation of wallner Lines via conchoidal fracturing. These introduce some really interesting visuals, especially when they oppose one another and generate these unique dynamic moire interferometry fringes.

Click image for larger version. 

Name:	wallner-linien.jpg 
Views:	1 
Size:	125.8 KB 
ID:	54478

Click image for larger version. 

Name:	12-Figure17-1.png 
Views:	1 
Size:	381.7 KB 
ID:	54479


https://en.wikipedia.org/wiki/Conchoidal_fracture

Fun stuff!