BACKGROUND:
Students are familiar with a world of color. They do
not realize that the colors that we use today in crayons and other items are
chemical "copycats" of colors originally made of finely crushed minerals. The first
paints were produced by crushing colored rocks and
mixing the powders with animal fats. Wax was also used in paints (encaustic painting),
dating back to ancient Greece. This incredibly durable medium was used to
adorn not only sculptures, but murals, boats, and buildings. The Greeks also
used wax paints in the earliest known form of easel painting.
Today's paints are a fluid suspension of crushed
matter in a liquid film that converts to a solid film when a thin layer is
applied to a metal, wood, stone, paper or other related material. Many
minerals have been or are used as paint pigments. The color black is
powdered coal. Dark blue is powdered lapis lazuli. Yellow is powdered
pyrite. Vermilion (light violet red) is powdered cinnabar. Red is powdered
hematite. Green is powdered malachite. Light blue is azurite. Very dark
green is powdered green clay (which is technically a variety of different
minerals). Gray is powdered molybdenite. White is powdered diatomite, which
is a rock. A number of these pigments are toxic to humans, so their
use has been discontinued. In many cases, pigments derived from plants have
been substituted for mineral colors.
PROCEDURE:
- If you have access to art books that illustrate
some of the great paintings of the 12th and 13th century, have the
students compare the colors and see if they can decide what minerals the
artists may have used to make them. The Rock and Minerals book
should be available for comparing of colors.
-
You may want to give students an
Internet research assignment that focuses on cave paintings. Have the
students try and learn what minerals were used as pigments.
Alternatively, have the students make a list of colors from minerals
and then research other colors derived from plants.
