Diamond material is already "cheap" if you just intend to use it on a drill or lens and not a prestige object. You can get a 99.9% perfect pure synthetic diamond plate bigger than your palm for like 500k, 90% of which being the new tooling for a reactor big enough to form such an object. In contrast a high quality 15 carat gem cut can easily go above $2M.
That's the price for a diamond pushing the limits of industrial engineering. You can also get a polycrystal plate of diamond with garbage optics for less than $200 if you just need it for thermal purposes
That's more like it :) Now imagine what would happen if that price went to $20 or even $2; even better if it was mono crystalline. That would be a game changer.
