This is the first clean link that I could find to the below.
Source: funnyjunk.com via Mary on Pinterest
To quote the original: “Fire glass produces more heat than real wood, and also is environmentally friendly. There is no smoke, it’s odorless and doesn’t produce ash. You are able to stay toasty warm without cutting down trees and the specially formulated glass crystals give off no toxic deposit.
Main Benefit: That shit looks like sorcery.”
That stuff has become very popular over the last couple of years. You could hardly watch an episode of Yard Crashers without them doing some fire feature that involved this product.
I thought that was just a natural gas setup below the glass