In 2018, there was a viral video that made a a huge splash and spread throughout the internet. It showed people gathering near the shore of Lake Michigan with UV flashlights and were searching for some kind of glowing rock. It was a palm-sized rock that was glowing brilliantly and to me, it looked like dragon eggs!
The specific rock in question? You guessed it… sodalite. This incredible phenomenon is caused by our favourite, mystical stone. But the question on our lips is why. Well, it’s because sodalite is a fluorescent mineral and it has the ability to reflect light. In this post, you get to know more about why sodalite glows and under what circumstances.
Why does sodalite glow?
Sodalite is a mineral widely used to make ornamental gemstones and is normally opaque in shape and they are almost translucent. It has been found out that a majority of sodalite gives away an orange- colored fluorescence when treated under UV lights.
The light from the ultraviolet rays acts as the electromagnetic radiation at a single wavelength and gets absorbed by the mineral. Then it re-emits the radiation at a much longer wavelength. Because of this phenomenon, the mineral appears to glow in the dark.
Sodalite can change colors too
Sodalite is popular for its color tricks with deposits that are widely found in Canada, South Greenland, Russia, and Norway. There are different kinds of rocks that have the capability to change colors. Hackmanite is the name given to the sodalite that has the ability to change colors.
It was observed that the mineral changes color on its own when persuaded by doses of light emitted from different wavelengths coming out of the electromagnetic spectrum. This includes both short-wave and long- wave ultraviolet light. You would be surprised to know that sodalite rocks can be boulders with several meters in radius.
Some of them not only changes color but fluorescence when treated with ultraviolet light. However, the process becomes reversible and they attain their original color when they are placed under sunlight for a prolonged time.
When you hold a small or large piece of sodalite mineral under an ultraviolet lamp, you have a mineral that’s glowing right in your hand. It only takes a few seconds to emit light. You can repeat this transformation endlessly. Several bars have installed their bar-tops made with sodalite to amaze the consumers.
Different types of sodalite:
This mineral is found in various complexes in huge quantities. A major part of sodalite is found in yellow or gray variants, and all of them fluoresces orange color. Here are some variants of sodalite.
Although the color appears as yellow under broad daylight, the pieces become deep purple when treated under the UV light.
It appears vibrant green under sunlight and looks like a gemstone. When exposed to UV rays, it becomes tenebrescent.
Certain countries have different varieties of sodalite, with both fluorescent and tenebrescent. It is mixed with other minerals to create unusual display specimens.
How can rock change colors like a chameleon?
During the early 1800s, geologists became well aware that alkaline sodalite has the tendency to change color when treated under different types of rays. Although the experiments with these light-emitting rocks were pretty much entertaining, the color change baffled many scientists.
And, in the late 1800s curiosities became a fashion. The scientists made use of radioactivity and began lots of experiments with these minerals. This includes exposing them to newer materials like radium and the newly discovered technology, the X-Rays.
Even after the scientific descriptions of the color changes, it came to be known that it was the Sulphur content in the mineral that caused changes in color. Sodalite experiences changes in chemistry and structure when hit by light.
Sodalite has an arrangement of atoms structured in a crystalline form. The mineral has some holes in the lattice structure. The collected atoms get filled up in these empty spaces, the sodium and chlorine atoms. In rare cases, the chlorine atoms are replaced by the Sulphur atoms.
These two atoms can’t be together, and when this happens, an empty spot is created. Under the UV rays, an electron from the cavity jumps to the Sulphur atom and to the next cavity as well. That’s when they change color.
So, that was all about the science behind the phenomenon of glowing sodalite. And, it glows because of the fluorescent mineral present in it, which re-emits the radiation at a longer wavelength.