This is Alexandrite, it’s also called “emerald by day, ruby by night”
It changes colour based on whether the light source is from the sun or from a candle.
It does this because Alexandrite strongly absorbs yellow light due to chromium ions in its crystal structure, leaving the other colours behind. Light from the Sun emits all colours, but it peaks in the green, and our eyes are most sensitive to green, so in Sunlight Alexandrite is green.
Incandescent lights are things like candles and filament light bulbs. They also emit all colours of light, but they peak far, far into the red, so there’s not nearly as much green or blue, so under those, Alexandrite is red.
Gemstones are awesome.
why am I thinking about an interesting idea for a crime novel plot right now
Fish pattern - blue version!
The single most badass photo ever. Dr. Leonid Rogozov performing his own appendectomy
This is even more badass than it looks. This happened in 1961, while Dr. Rogozov was the only doctor on an Antarctic Expedition. When he got ill the nearest Russian station was more than 1000 km away and nearby foreign stations had no aircraft.
Even then it wouldn’t have mattered because he did this in a fucking blizzard, with a local anaesthetic while he had a driver and a meteorologist hand him crap and hold a mirror. It took him two hours, with breaks because of “general weakness.”
He was back working 2 weeks after he did this. Legend.