lyijykyniin

Lyijykynä, often referred to as a pencil in English, is a writing and drawing tool. Despite its name, it does not contain actual lead. Instead, the core, or "lead," is composed of a mixture of graphite and clay. The ratio of graphite to clay determines the hardness and darkness of the mark the pencil makes. Higher graphite content results in softer, darker lines, while more clay produces harder, lighter lines.

The graphite-clay mixture is typically encased in a wooden barrel, which is usually hexagonal or round to prevent rolling. The wood is often cedar, chosen for its ease of sharpening and pleasant aroma. When the pencil is used, the graphite-clay mixture wears away, leaving a mark on the writing surface. This process is a form of abrasion.

Lyijykynä are manufactured in various grades, indicated by a system of letters and numbers. For example, 'H' grades are harder and lighter, suitable for technical drawing, while 'B' grades are softer and darker, preferred by artists for shading and sketching. The 'HB' grade is a common middle ground, suitable for general writing. Erasers are often attached to the end of lyijykynä, allowing for the removal of marks made by the graphite-clay core. The invention of the modern lyijykynä is attributed to Nicolas-Jacques Conté in 1795, who developed a method to mix graphite powder with clay and fire it in a kiln.