This was commissioned by my SIL's co-worker, a history buff and fan of the Knights Templar.
The white glass appears to be almost a clear/white mix. There is an odd texture that makes me believe it, and it has been notoriously difficult to cut. Many glasses that are supposed to be a pain (Youghiogheny comes to mind) work fine for me. This one mis-broke every time. It is of unknown manufacturer, as I bought it from a local shop and didn't note the ID number which has long since worn off.
I had to repair multiple pieces while it was still being made. At one point I was soldering outside and it managed to slide off my little portable table, breaking pieces. Thermal shock while soldering broke another, something I've never had happen before or since. I'm rather relieved to have gotten it this far.
Viewing it completed, I think I'd prefer it with a border, even if it's just zinc came. A wooden border would also be nice, but I think both are ruled out because the thinness of the border.