Sciencebloggin - :))

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.

Y’ever read something and have understanding that has eluded you interminably suddenly stop, curl up, and snuggle neatly into a fold in your brain because a new way way opened to it?

Blue lava erupting from the Kawah Ijen volcano in Indonesia. The mountain contains large amounts of pure sulfur, which emit icy violet colors as it burns. | by Olivier Grunewald [2048 × 1362]

Fluorite

Locality: Bergmännisch Glück Mine, Frohnau, Erzgebirge, Saxony, Germany

so international space station astronauts apparently dropped a tool bag during a spacewalk. and if you look outside when the ISS is in your region, you can see it with binoculars

The tool bag is now orbiting our planet just ahead of the ISS with a visual magnitude of around 6, according to EarthSky. That means it is slightly less bright than the ice giant Uranus, the seventh planet from the sun. As a result, the bag  —  officially known as a crew lock bag  —  is slightly too dim to be visible to the unaided eye, but skywatchers should be able to pick it up with binoculars.  To see it for yourself, first find out when you can find spot the space station over the next few months (NASA even has a new app to help you). The bag should be floating two to four minutes ahead of the station. As it descends rapidly, the bag is likely to disintegrate when it reaches an altitude of around 70 miles (113 kilometers) over Earth. 

she's fucking magnificent