Glowing Rocks at the Natural History Museum

What makes these rocks glow, but others not?

by Angel Abrego

While exploring the Natural History Museum I stopped at a dead end to find glowing rocks. I've never seen glowing rocks until now. Then I noticed some of those rocks I knew about. I knew as soon as I saw those rocks I had to find a question for it. So I started to think what can I say. Then it came to my mind. How does these rocks glow and others don’t? How did scientist discovered the glowing rocks? Well I managed to find answers and let me explain how glowing rocks work.

There’s many things that make a Fluorescent mineral. There's about 17 elements that make rocks/minerals glow, but today I’ll be focused on only one mineral. Lanthanum is one of the 17 “Rare Earth Metals” family. Even if it is a solid doesn’t mean it can’t help it glow because that solid could have a important chemical formula that may help the mineral glow. Lanthanum is a molecule that when exposed to Ultraviolet lights, the effect is it actually bounces some light out. According to the Natural History Museum display, “Some minerals contains atoms with electrons that are boosted to higher energy level by Ultraviolet light. These electrons instantly fall back to their original energy levels, giving off energy in the form of visible light”. To keep it simple some atoms including Lanthanum have electrons that respond positively when exposed to a UV light which causes them to glow because they bounce up on the energy level than bounce back down.

Now some people might get confused between fluorescence and phosphorescence. There's a big difference between these two. A fluorescent mineral reacts immediately as soon as a UltraViolet light hits it but doesn’t glow in the dark or light without a UV light. A phosphorescent mineral on the other hand absorbs light no matter if its a UV light or a normal light. This glowing effect takes long for this to happen because it absorbs slowly, but it can glow by itself in the dark and time goes by it slowly loses its glowing effect. This is used to make glow sticks which is man made while fluorescent is naturally made. But that doesn’t mean phosphorescence isn’t naturally found but still it's mostly made by people, so that's why it's kind of different.

So in case you still are confused let me explain more clearly. The cause of rocks Fluorescing is because of what’s inside the 17 Rare Earth Metals. Inside the mineral is where all the magic happens. The electrons in the minerals bounce up then down when exposed to a UV light. As soon as they come back down they make a fluorescing effect which causes a glow in the rock. Phosphorescence is different because it absorbs light and doesn’t respond immediately as well. This is hard because if they both glow which one causes a rock to glow. They both have electrons but the effect happens inside the molecule so I guess both help the rocks glow. They both are actually found naturally inside rocks. In conclusion the Rare Earth Metals (Atomic number 58-Atomic number 71) can cause this rare effect underground. Now you know the confusion and beauty of nature scientifically--but that doesn't mean everything that glows does the same thing, but they do have some parts in common.



Vocabulary:


Wave Length: The distance between successive crests of a wave, especially points in a sound wave or electromagnetic wave.


Fluorescence: the visible or invisible radiation emitted by certain substances as a result of incident radiation of a shorter wavelength such as X-rays or ultraviolet light.


UltraViolet: Ultraviolet is electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation is present in sunlight constituting about 10% of the total light output of the Sun


Electrons: a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.




Websites:


Fluorescent Minerals and Rocks: They Glow under UV Light!


What Elements Glow in the Dark? | Sciencing


Mineralogy Database