Color pencil materials and uses

The main components of the pencil lead are graphite. Early pencils contain lead, but now people use the pencil lead is the main component of graphite and bonding agent, no longer lead, harmless to human body. Pencil refill is made of graphite and clay mixed by a certain percentage, in which the higher the content of graphite pencil is soft, the higher the content of clay pencil harder, hard and soft pencil with H and B to that, H that hard B Said soft, HB said moderate. Pencil to the hardness of the refill is divided into soft, neutral, rigid three. The soft lead-core production of raw materials because of the ratio of more raw materials of graphite, clay, less than the ratio. Rigid lead-core production of raw materials and soft lead lead to the opposite. While the neutral lead-graphite and clay with the ratio is quite.

Color pencil, which is often said that the crayon, mainly for painting a lot of people may not know, a pencil can also identify the authenticity of diamonds. Diamond wetting with water, with a pencil on it in the above characterization, true diamond surface will not leave traces of pencil across. With crystal, glass, tourmaline and other production of fake diamonds will leave traces.