Beards are divided into brown, black and red, which are determined by pigments. A few years ago, scholars discovered the secret of pigments in hair (including beards, of course): there are metal elements in hair pigments. Black hair contains copper, cobalt and iron; the brown color of hair is caused by titanium; and the red color is caused by molybdenum. Emperor Friedrich I of Germany had a red beard, so he was nicknamed the Red-bearded Emperor. Later, his beard turned silver-gray, which may be caused by the loss of pigment. Ancient Greek philosophers Plato, Socrates and Aristotle seemed to feel that wisdom existed in beards, so they all grew beards. Recently, it was reported that research has confirmed that the content of copper and zinc in the beards of smart and capable men is higher than that of ordinary people. Like nails, beards are also a variant of horns, evolved from horns, and are composed of amino acid chains. Millions of years ago, the world's first wild animals were covered in horn-like scale armor. After continuous evolution, the horns turned into thorns, and then the thorns evolved into hairs, so the hairs are the most at the edges and corners. On a person's face, the upper lip and chin are exactly two corners, so the beard grows thickest here, and the amount of beard is also related to the size of these two corners. Some psychologists believe that a beard can reflect a person's character. This is unfounded. Charlie Chaplin and Adolf Hitler both had mustaches. Did they have the same moral character? Apparently not. But a beard can indeed make up for the flaws in a person’s face. The Roman Emperor Hadrian covered his face with a beard. Juan Carlos I of Spain had facial skin disease, so he wore a beard to cover up his ugliness. Those with a flat jaw can make up for it by growing a pointed beard; those with thin cheeks can have a cheek beard to make their face look fuller; a larger mustache is especially suitable for those with an oversized nose, as it can make the facial features appear coordinated. Shaving your beard properly can make a person more beautiful; on the contrary, it may also be self-defeating. Beard is a part of a man's body. A beard can analyze a person's health status. American scientists can determine whether a person is malnourished, suffers from congenital mental illness, diabetes or metabolic disorders from the laboratory analysis of a beard.