the Diamond Planet.........

Diamonds are crystals of pure carbon,which form under high pressure and intense heat.They mostly form in earth's mantel,the layer between the crust and surface layer through a process which takes 1 billion to 3 billion years . They are brought closer to surface of the earth by deep volcanic eruption by a magma which cools into ignious rocks known as kimberlites and lamproites. One such rare diamond has been found by scientists orbitting pulsar (A highly magenetized,rotating neutron star that emitesa beam of electromagnetic radiation) .According to scientists it could be a star that has been crushed into a much smaller planet made largely of solid diamond. They deduce that this planet,could be causing detectable gravitational pull, orbiting the pulsar  Further examination reveales that although the planet is relatively small (60,000 km diameter, or five times bigger than the Earth) its mass is slightly more than that of Jupiter. The high density of the planet gives a clue that it is made up of  carbon and oxygen.
such planets known as carbon planets also ref as diamond planet, which might also be floating  near the galactic core or globular clusters orbiting the galaxy, where stars have a higher carbon-to-oxygen ratio than the sun does. When old stars die, they spew out large quantities of carbon. As time passes and more and more generations of stars end, the concentration of carbon, and carbon planets, will increase.The spectra of carbon planets would lack water, but show the presence of carbonaceous substances, such as carbon monoxideThese could have formed by disruption of a carbon-producing stars. .
Lets understand anatomy of carbon a planet....these planets could  have a core rich in iron and steel surrounded by molten siliconcarbide and titanium carbide,  layered in carbon in the form of graphite,with a thick layer of substratum of diamonds if there's sufficient pressure .The surface  containing frozen or liquid hydrocarbons and carbonmonoxide. There might be a great lack of water on a carbon planet.  Extraterrestrial life might be possible if water is present, but the highly reducing environment could result in metabolism taking the opposite approach to that of terrestrial life, with oxygen-bearing compounds being eaten as food to react with the carbon-based atmosphere.Carbon planets are predicted to be of similar diameter to silicate and water planets of the same mass, potentially making them difficult to distinguish. The equivalences of geologic features on Earth may also be present, but with different compositions. For instance, the rivers might consist of oils. If the temperature is low enough (below 350 K), then gases may be able to photochemically synthesize into long-chain hydrocarbons, which could rain down onto the surface. .