Right, per this thread's link, seems to be circa 2009:

“In 2009… what emerged from the furnace was a brilliant blue…”

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And per the previously link...

pacificmint on Jan 29, 2021 | next [–]

Previous discussions:

- https://news.ycombinator.com/item?id=25807199

- https://news.ycombinator.com/item?id=25886601

Two articles about the discovery:

- https://www.npr.org/2016/07/16/485696248/a-chemist-accidenta...

- https://www.bloomberg.com/features/2018-quest-for-billion-do...