By carbon 14 dating

Before the discovery in 1779 that graphite when burned in air forms carbon dioxide, graphite was confused with both the metal lead and a superficially similar substance, the mineral molybdenite.Pure diamond is the hardest naturally occurring substance known and is a poor conductor of electricity.Modern carbon chemistry dates from the development of coals, petroleum, and natural gas as fuels and from the elucidation of synthetic organic chemistry, both substantially developed since the 1800s.buckerminsterfullerenes, or “buckyballs,” and cylindrical fullerenes are called nanotubes.

(Coals are elemental carbon mixed with varying amounts of carbon compounds.Coke and charcoal are nearly pure carbon.) In addition to its uses in making inks and paints, carbon black is added to the rubber used in tires to improve its wearing qualities.Carbon is the cosmic product of the “burning” of helium, in which three helium nuclei, atomic number 4, fuse to produce a carbon nucleus, atomic number 12.In the crust of Earth, elemental carbon is a minor component.Diamond and graphite occur naturally on Earth, and they also can be produced synthetically; they are chemically inert but do combine with oxygen at high temperatures, just as amorphous carbon does.

Fullerene was serendipitously discovered in 1985 as a synthetic product in the course of laboratory experiments to simulate the chemistry in the atmosphere of giant stars.

Because it conducts electricity but does not melt, graphite is also used for electrodes in electric furnaces and dry cells as well as for making crucibles in which metals are melted.

Molecules of fullerene show promise in a range of applications, including high-tensile-strength materials, unique electronic and energy-storage devices, and safe encapsulation of flammable gases, such as hydrogen.

Graphite, on the other hand, is a soft slippery solid that is a good conductor of both heat and electricity.

Carbon as diamond is the most expensive and brilliant of all the natural gemstones and the hardest of the naturally occurring abrasives. In microcrystalline and nearly amorphous form, it is used as a black pigment, as an adsorbent, as a fuel, as a filler for rubber, and, mixed with clay, as the “lead” of pencils.

Isolated finds around the world in regions where no sources are indicated have not been uncommon.