Last week, Marathon Fusion, a San Francisco-based energy startup, submitted a preprint detailing an action plan for synthesizing gold particles via nuclear transmutation—essentially the process of turning one element into another by tweaking its nucleus. The paper, which has yet to undergo peer review, argues that the proposed system would offer a new revenue stream from all the new gold being produced, in addition to other economic and technological benefits.
Transparent aluminum was around in 2018 source
a lot longer than that.
Synthetic corundum, spinel and others have been around for over 120 years, and optically transparent uncoloured sapphire glass for over 80 years. They are just aluminium oxides.
ALON is just the new hotness, and not as good as some others in terms of visible light transparency.