light in solid form

When a gas changes phase into solid it is called deposition (or desublimation). Examples are frost, hoar frost, and snow forming in clouds. Each of these changes are from water vapor to ice. So what would it be called to go from energy and light to a solid (kinda-of)?

Fulgurite (image from the NASA blog)

Fulgurite - created when lightning strikes sand or silica rich dirt. The silica it turned into glass due to the high temperatures of the lightning. Otherwise know as "fossilized lightning". Some of this stuff is for sale - for fairly cheep on eBay... I'm considering getting some.