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Diamond and Graphite

Last updated date: 19th Jul 2024
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Introduction to Diamond and Graphite and Their Properties

Diamond and Graphite are called the allotropes of carbon. Chemically, these minerals consist of carbon atoms with different physical properties. In general, these minerals are known referred to as polymorphs, with the same type of chemistry, but of different crystalline structures.


In these carbon allotropes, the atoms consisting of carbon atoms in Diamond and Graphite, are bound together by strong covalent bonds of different arrangements.


Precious stone and Graphite both have shift structures, and both are pure carbon, which represents their diverse properties. However, the particles of Graphite join the three atoms of carbon and get associated with the plates, parallel to each other. The Diamond particles enter the four atoms of carbon in a gem frame.


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Let us understand the structure and the uses of Diamond and Graphite in detail.


Structure of Diamond

All carbon atoms of the Diamond are said to possess strong chemical bonds of the four other carbon atoms, thereby making a perfect tetrahedron structure and completing the crystal. Here, the carbon atoms are of sp3 hybridized, and the bond lengths of the carbon-carbon atom are equal. Therefore, the Diamond forms a three-dimensional network with strong covalent bonds.


Diamond has a melting point of about 3843 K, which is very high, and a high density of about 3.51 g/cm3. Since its valence electrons are involved in the C-C sigma covalent bonds, it is known to be a poor conductor of electricity, and thus they are localized and are not free to conduct the electricity.



Allotropy is the property where elements exist in two or more forms. They exist in the same physical state but due to the difference in their structures, they are different in their abilities. The difference in these properties is because whenever these elements are formed, different temperatures and pressure are provided while extraction. Because of this, stability is different. These in turn result in differences in physical properties. The allotropes are bonded in a different manner but contain the same basic foundational element.

Some Elements that possess the property of allotropy are Sulfur and Carbon.

The allotropes of carbon are Diamond, Graphite, and Fullerene. The allotropes of sulfur are Monoclinic sulfur, Rhombic sulfur, and plastic sulfur. There are as many as 30 allotropes of sulfur to be known till now.


Mechanical Properties of Diamond

  • Hardness

Diamond is the hardest and naturally known material on both the Vickers and Mohs scale. The great hardness of Diamond relative to other materials has been known since antiquity and is the source of its name.

  • Toughness

Another mechanical property somewhat related to hardness is toughness. It is the ability of the material to resist breakage from forceful impact. The toughness of a natural diamond has been found, when measured as, 

7.5–10 MPa · m1/2.


Uses and Applications of Diamond

Some applications of Diamond are listed below.

  • Diamond is a well-known material to be the hardest substance on Earth. It is used in the making tools which are utilized for cutting, grinding, drilling, and more.

  • Diamond is used to manufacture filaments that are made of tungstens, used in light bulbs

  • Diamond is used in jewelry making.

  • They are used by most surgeons in the process of cataract removal from the eyes as a high-precision instrument.

  • The Diamond's hardness makes it very useful for purposes where extremely tough material is needed.

  • The cutting edges of discs are used to cut the bricks and concrete are tipped with diamonds.


Let us understand the structure of Graphite.


Structure of Graphite

All the carbon atoms present in the Graphite are said to have stable chemical bonds compared to that of the other three carbon atoms, thus making the sheets look like a chicken wire; the weak form of the forces that hold the sheet quickly. When we are composing with a pencil on paper, it is these sheets that separately slide to desert the graphite pieces as a blemish on the Paper.


The carbon atoms present in the Graphite structure or graphite molecular structure are of sp2 hybridized, and they are directed in the same plane, thus forming the hexagonal rings. The rings have several layers of particles. Graphite is said to exhibit a low electrical conductivity of a low density of about 2.26 g/cm3.


Types and Varieties of Graphite

The principal types of natural graphite, each occurring in various types of ore deposits, are given below.

  • Flake graphite or small crystalline flakes of Graphite occurs as flat, isolated, plate-like particles with hexagonal edges if unbroken. Edges can be irregular or angular when broken.

  • Amorphous Graphite is very fine flake graphite.

  • Lump or Vein graphite forms in fractures or fissure veins and tends to be large platy intergrowths of acicular or fibrous crystalline aggregates, and is possibly hydrothermal in nature.

  • Highly ordered pyrolytic Graphite called Graphite with an angular spread between the graphite sheets of below 1°.

  • Sometimes, the name "graphite fiber" is used to refer to carbon-fiber-reinforced polymer or carbon fibers.


Applications of Graphite

  • The weak intermolecular forces of Graphite make it a useful material.

  • Graphite powder can be utilized as a lubricant in the form of powder or dispersion material.

  • It is widely used as a lead in pencils, mixed with clay.

  • Graphite is used in the electrode manufacturing of carbon, employed in the electrolytic cells because it is an excellent conductor of electricity.

  • Damond can also utilize in the making of graphite crucibles because it possesses high melting points.

  • It is widely used in moderators and nuclear reactors.

  • Also, Graphite is used to make the non-reactive electrodes for electrolysis since it can conduct electricity without participating in the process chemically.


Quick Summary

  • Diamond and graphite are allotropes of carbon that exist to provide different properties.

  • Diamond and graphite are used in a variety of applications.

  • The atoms in graphite and diamond are strongly bonded with covalent bonds, forming different arrangements with each other. 

  • Diamonds are used in Jewelry making, construction, minor industrial applications, and surgeries.

  • Graphites are used in stationery, lubricants, industries, or nuclear reactors.

  • Diamond and graphite are obtained in nature, however, they can also be artificially produced.

  • In diamond, carbon atoms are arranged tetrahedrally whereas in graphite the carbon atoms are arranged in an infinite array.

Did You Know?

  • Diamonds are excavated from the earth with a high temperature and pressure.

  • Diamonds are made up of 100% carbon and are stable solids.

  • Diamonds are formed about 100 miles below the earth and even might get eroded from volcanic eruptions.

  • Diamonds actually come in various colors. However, the color palette is from pale yellow to white. But they also come in different colors like Red, blue, Green, Orange, pink, and black

  • The only thing that can scratch a diamond surface is the diamond itself.

  • India is the World's original source of Diamonds

  • Graphite is the only non-metal that conducts electricity.

  • Graphite is produced from coal and not mined from the ores. 

  • Graphite was named due to its ability to leave a mark on paper or any of the objects.

Why is Diamond So Rare?

  • Diamonds, the most expensive yet charming gem, were first made a billion years ago.

  • Diamonds possess exceptionality because of their low excavation rate. 

  • Only 50% of the total extracted diamonds are said to be highly precious and attractive in the market. 

The rarity, difficulties in mining, durability, cut, clarity, color, and carat of diamonds make them expensive and in demand. Only 30% of the mined diamond stones match the standard gem quality that is required. It is this rarity of stone that makes them the world's most expensive diamond.

Sample Questions:

  1.  What is a diamond and how is it made?

  2.  what is graphite and explain its occurrence

  3. Why Do graphite and diamond have the same structure?

  4.  differentiate between diamond and graphite

  5. Give some uses of diamond 

  6. Give some uses of Graphite

  7. Explain Mechanical properties of diamond and graphite

  8. What type of bonding is present in diamonds?

  9. Structure of diamond and graphite

  10.  Why is Graphite used in electrical work?

This is a concise introduction to diamonds and graphite, the two allotropes of carbon and their properties. Focus on their physical properties and learn how the same atoms of carbon behave in a different way. 

FAQs on Diamond and Graphite

1. Are diamonds and graphites allotropes?

Allotropy is a phenomenon where the same elements exist in two or more forms. And the elements possessing this property are called allotropes. Allotropes differ in both physical and chemical properties. Allotropes can be defined as structural modifications made in the same element. Both diamond and graphite are made up of carbon. But, due to the difference in their structures and positioning of atoms, both the materials are different in nature. And hence diamond and graphite are allotropes of carbon. Graphite has different properties as compared to graphite due to the difference in its structures. 

2. What is the difference between diamond and graphite?

Diamond and graphite are allotropes of carbon. However, the difference in the properties is due to the different structures. Visually, diamond is transparent and graphite is opaque and black. Diamond is known as the hardest substance in nature but graphite is a soft substance. The density of Diamond is more as compared to graphite. Diamond Crystallizes in an isometric system whereas graphite crystallizes in the hexagonal system. Diamond is a poor conductor of electricity but graphite is a good conductor of heat and electricity.

3. What are the similarities between diamond and graphite?

Diamond and graphite are allotropes of carbon, but some of their properties are different. Still, they do have some similarities between them. Both diamond and graphite are made up of carbon. They are extracted naturally and they can be produced artificially as well. Graphite is a stable solid and even if an oxygen environment is provided, they are difficult to burn. Both graphite and diamond are mined for industrial purposes. Using the Geothermal processes in earth, diamond and graphite are produced on a large scale. 

4. Explain the Occurrence of Graphite.

Graphite happens in metamorphic rocks as a result of the sedimentary reduction of carbon compounds during metamorphism. Graphite also occurs in meteorites and igneous rocks. Minerals that are associated with Graphite include calcite, quartz, tourmaline, and micas. The principal export sources of the mined Graphite are in tonnage order: China, Canada, Mexico, Madagascar, and Brazil.

Graphite occurs in meteorites with silicate and troilite minerals. Small graphitic crystals in meteoritic iron are known as Cliftonite. Some microscopic grains have distinctive isotopic compositions, to indicate that they were formed before the Solar system. 

They are one of about 12 well-known types of minerals that predate the Solar System and also have been detected in the molecular clouds. These minerals were also formed in the ejecta when the supernova exploded or low- to intermediate-sized stars expelled their outer envelopes late in their lives. Graphite is the second or third oldest mineral in the Universe.

5. Explain the Material Properties of Diamond?

The Diamond is a solid form of pure carbon where the atoms are arranged in a crystal. Solid carbon is available in various forms called allotropes based on the chemical bond type. Diamond is one of the most common allotropes of pure carbon. In Diamond, the bonds are sp3 orbital hybrids, and the atoms form tetrahedra with each bound to four nearest neighbors. 

Tetrahedra are rigid, and the bonds are strong, and with all known substances, per unit volume, Diamond has the greatest number of atoms, which is why it is both the least and the hardest compressible. It also has a greater density, ranging from 3520 kg/m3 in pure Diamond, and 3150 to 3530 kilograms per cubic metre (which is about three times the water density) in natural diamonds.