[name]
Beryllium
[intro]
Beryllium forms a passivating oxide layer and does not react with air or water. 
It is lighter than aluminium, yet it is much stronger. 
Consequentially, it is used in a wide range of applications, like aerospace, mirrors, military ... 
Furthermore, Beryllium is virtually transparent to X-rays. 
It is also used in nuclear reactors to reflect and absorb neutrons. 
Another interesting application area is acoustics. 
The combination of high rigidity and low density makes Be a useful material for high-end high-frequency speaker drivers.

While Be is very useful, its processing and commercial use poses some technical challenges related to the toxicity of Be-containing dusts.
Be can cause a chronic life-threatening allergic-type lung response called berylliosis.
[image]
This is the box with which we started in 2011 in our periodic table.
 The pure metal is encapsulated in glass.
The second object is a mineral aquamarine containing Be. It is translucent when illuminated.
The last object is an application for radiation windows in X-ray tubes.