My first thought was FOGBANK[0] - a material that was used in some US nuclear weapons that was lost to time, and reverse engineered.<a href="https://en.wikipedia.org/wiki/Fogbank" rel="nofollow">https://en.wikipedia.org/wiki/Fogbank
sillywalk · · focus · HN ↗
<a href="https://en.wikipedia.org/wiki/Fogbank" rel="nofollow">https://en.wikipedia.org/wiki/Fogbank