Colored pencil Colored pencil A colored pencil (US-English), coloured pencil (UK-English, Canada-English), pencil crayon (UK-English, Canada-English), lead or coloured/colouring lead (Newfoundland-English) is an art medium constructed of a narrow, pigmented core encased in a wooden cylindrical case. Unlike graphite and charcoal pencils, colored pencils’ cores are wax- or oil-based and contain varying proportions of pigments, additives, and binding agents. Water-soluble (watercolor) pencils and pastel pencils are also manufactured as well as colored leads for mechanical pencils. Colored pencils vary greatly in terms of quality and usability; concentration of pigments in the core, lightfastness of the pigments, durability of the colored pencil, and
White lead for bearings and in machine shops. What is commonly known today as the "Dutch method" for the preparation of white lead was described as early as Theophrastus of Eresos (ca. 300 BC), in his brief work on rocks or minerals, "On Stones" or "History of Stones." His directions for the process were repeated throughout history by many authors of chemical and alchemical literature. The uses of cerussa were described as an external medication and pigment. Clifford Dyer Holley quotes from Theophrastus' "History of Stones" as follows, in his book "The Lead and Zinc Pigments". Lead is placed in earthen vessels