See https://www.m-disc.com/technology.html https://www.m-disc.com/technology.html "The M-DISC engraves data into a patented rock-like layer that is resistant t

See https://www.m-disc.com/technology.html https://www.m-disc.com/technology.html "The M-DISC engraves data into a patented rock-like layer that is resistant to extreme conditions of light, temperature and humidity"