The glowing fluorite

name

Miners also say fluorspar for fluorite.

Composition

Fluorite consists of the elements calcium and fluorine.

Occurrence

Fluorite is found all over the world.

You often find it together with the minerals:
Quartz, calcite, barite, Galena (galena),
sphalerite (sphalerite) or pyrite (cat´s gold).

Use

Fluorite is an important raw material

It helps as a flux in the melting of
metals.
Through it, the melt becomes liquid
faster.
That´s why you save fuel.
So the fluorite also came to the name
fluorspar.

Microscopes or telescopes have fluorite lenses.
Through them, even ultraviolet light
shines.
Glass lenses, on the other hand, filter this light.
Because pure fluorites are rare,
huge monocrystals are grown in
factories.

Hydrofluoric acid is also produced from fluorite.
The acid is dangerous, but can etch glass.

The toothpaste contains fluoride.
It cures your enamel and
protects your teeth from tooth decay
and nasty holes.

Crytal form

Which forms do the fluorite crystals have?

Mostly you will find cubes or octahedra.
Octahedra consist of two pyramids.

Toughness

Fluorite has a hardness of 4 on the
Mohs hardness scale.
Diamond has the hardness 10,
that´s why it´s the hardest mineral in
the world.
Sebum is very soft and has the
hardness 1.

The fluorite is harder than your
fingernail.
You can´t scratch it.
He is too soft to scratch a glass plate.

Fissionability

If you hit a piece of fluorite with a
hammer,
arise straight and smooth split pieces.
This is a typical sign of good
cleavability.

Sometimes you can see such gaps in
the crystals.
They look like cracks in the glass.

Colour

The crystals of fluorite look colorless.
But in nature that rarely happens.
Tiny amounts of other elements color
the crystals in all possible colors:
yellow, pink, purple, even black,
green, blue or brown!
Some colored fluorites have their own
name.
The golden yellow fluorite is called
Honigspat,
the purple Stinkspat.
Rare and precious are pink fluorites.
You can only find them in the Alps.

Some fluorites glow in the dark.
For that you have to irradiate them
with ultraviolet light.
How to create the glow without this
light,
You see in our exciting experiment.
Click on the video!

The experiment is carried out by Christina Seifert, museum educator of terra mineralia.

Das Leuchten

Scientists call this luminous
luminescence.
For the fluorite shine, it needs energy.
The fluorit gets it from the ultraviolet light
or by heating.

But how exactly does that work?
All atoms concist of a nucleus,
around him electrons circle in bowls.

The high-energy UV light lifts the
electrons
on the outermost shell to the next
higher one.
When the outside electrons fall back,
they release this energy in the form of light.
The mineral shines!

Does the light stop, when the UV light
is off?
The you have seen the fluorescence.

But if you see the light shine longer,
as with pointers on the kitchen clock?
Then you see the phosphorescence.
There is a persistence.

Riddle

HAve fun with our little FluoRiddle!

If you have paid close attention, you
will quickly find the solutions.