This series of videos show just what is possible with intense beams of sunlight. They do not all use sun dishes, but the physics is near identical in form. The inference from these modern solar technologists is that an ancient with a dish could pretty much deliver the same techniques (excepting the computer controls). Materials transforms and cutting are all practical without recourse to anything more exotic than a parabolic concetrator.
Solar sinter project
AMAZING this guy is making glass from sand by pointing a beam at it. He even makes pots with just a guided beam
Big Ass Fresenl lens These guys were just having fun and show how quick a beam will cut thru rocks.
Fresnel melts metals easily
5000 Suns this guy is getting famous for showing the potency of the mosaic method of concentrating sunlight
The guys at Green energy are doing a great job showing a vast array of possibilities. This link shows one, it links to plent yof others at the end. Just point and click.
”Solar Death Ray” more fun with great marketing
2700 degs F
Stirling Engine Solar
Glass cutting with a dish
If you have any links that you think would make good additions to this post please post them at the bottom of the page. If any links have ceased to work please mention it in the same spot.