This is a 64″ spot Fresnel Lens with a max temperature above 3000˚F.
http://www.greenpowerscience.com/
The concrete and rock shatters from the temperature shock. Slowly adding heat allows for melting. The rock was exposed for 60 seconds and the two pieces heated 8 ounces of water from 68˚F to about 130˚F within seconds.
Post time: Jul-12-2017