Well the idea is pretty simple, any thing that needs to be made with glass would also require this skill.
This skill would also unlock the ability to build a furnace. If you can make it so you can dig sand(similarly to clay and lime etc) and you fill your inventory with sand and burn it to make glass panes. Perhaps throw in some new inspirationals too like you get the fallen bricks.
Just thought that as we cant currently make glass panes and this something that i've heard alot of people would like this would be a good way to go about it but just perhaps make it a high 'Arts and crafts' skill.
What do you guys think?