The science of how diamonds form is a good starting point for a child seeking a research topic on diamonds. They are made of pure carbon that crystallizes into diamond when subjected to very high pressure and very high temperatures over a long period of time. Children can research how the heat and pressure rearranges the chemical structure of carbon to transform it into the highly regular crystalline pattern that constitutes diamonds.
Jewelers appraise the value of diamonds according to the "four C's": carats, clarity, cut and color. Children can study the standards for each of these values and the science and expertise that goes into rating a diamond in each category. Carats refer to the total weight of a diamond. Clarity is a diamond's rating on transparency and the size and number of flaws, known as inclusions. Cut refers to the style and precision with which a diamond's facets have been cut to enhance its beauty. Color includes both hue and intensity of a diamond's color.
While most diamond jewelry uses clear diamonds, there are also diamonds in a variety of other colors, such as pink, black, blue and yellow. One topic a child could research for a science project on diamonds is what chemical additives cause the different colors and why. Nitrogen makes a diamond yellow, for example, while boron adds a blue tint. The science project may also include research into which colors of diamond are considered most valuable.
Only about 20 percent of the diamonds in the world are of a high enough grade to use in jewelry. A majority of the diamond mined in the world is powdered for use in industrial applications, such as drill bits, saws, precision cutters and even dentist drills. Diamond is one of the hardest substances in the world and adds strength and durability to cutting tools. Children can research the many applications of diamonds outside of the world of jewelry.