How come this element that shatters some metals does no harm when it touches our hands?

The moment you hold gallium in the palm of your hand, it becomes slippery as if it were a liquid and slips through your fingers. It leaves behind only a sticky feeling and small smudges. So how can it be explained that gallium has the power to almost destroy most substances, yet it does not harm the human body?

And how does this happen? In fact, the reason gallium causes metals such as aluminum and steel to melt is because it reacts chemically with them. Just as water causes iron to rust but does not harm our hands, a more accelerated version of a similar situation applies to the interaction of these elements (gallium, aluminum).

When this element combines with aluminum, it forms an alloy called amalgam. This alloy seeps into the atomic crystal structure of aluminum and dissolves it, making it brittle. Thus, solid aluminum can easily disintegrate when combined with gallium, and gallium causes structural damage to the substance with which it interacts.

Surprisingly, gallium requires very little intervention to accomplish this. Even a very small amount of gallium on an aluminum and steel material is enough to form the alloy.

The element melts and becomes a liquid quite easily, but it requires very high temperatures to boil. It expands when it freezes and is one of the few substances that can do this. In addition, the alloy obtained as a result of combining metals such as gold, nickel and copper with gallium is seen to harden at oral temperature and this alloy is used as a filling material in dentistry.

In summary, the fact that gallium becomes liquid in our hands but damages different metals is the result of its chemical reaction with these metals. For example, nothing happens when we come into contact with water and salt separately, but when these two compounds come together, the salt dissolves in the water.