Why is diamond so hard

Diamonds continue to sparkle despite all the global gloom
Value spiked 30% in 2011 and are expected to stabilise in 2012 . Read houston diamond exchange

Why is diamond so hard?

Its so hard because it consists of very small atoms (carbon) that are then tightly packed together and linked via covalent bonds (bonds where two atoms share an electron). It is the combination of very tight packing and very tight linking that results in diamond being so hard. The diamond is very hard because it has crystallized in a specific atomic shape that is the result of pressure and heat on earth created at depth of 140-150 km( sometime it has crystallized at 300-400 km under the earth and at exposed to high pressure ranging approximately between 45-60 kilobars and temperature ranging between 1652-2372 F(900-1300 C) during a very long time and often brought to the surface by a volcanic eruption..

Since a diamond is in essence an allotrope of carbon, you might think that carbon should be just as hard as a diamond, but this is not the case. The reason that a diamond is so much stronger than regular carbon is because the molecules in the diamond have been rearranged. Each atom of carbon in a diamond is the same distance from each other and is close enough that they can not move. This forms a very rigid network of bonds that help to make a diamond so strong.

Harder than diamonds

Diamonds are very very hard, so hard that they rate a 10 out of 10 on Mohs scale of mineral hardness.

Now two rare natural substance have been discovered that are both harder than diamond.

Only small amounts of wurtzite boron nitride and lonsdaleite exist naturally or have been made in the lab so until now no one had realized their superior strength. A simulation showed that wurtzide boron nitride could withstand 18% more stress than diamond, and lonsdaleite 58% more. If the results are confirmed with physical experiments, both materials would be far harder than any substance ever measured.

why is a diamond so hard? But now harder minerals have been found to exist (Image: Isifa Image Service sro/Rex Features) Beautiful, expensive and very hard. But now harder minerals have been found to exist (Image: Isifa Image Service sro/Rex Features)

The first, wurtzite boron nitride has a similar structure to diamond, but is made up of different atoms.

The second, the mineral lonsdaleite, or hexagonal diamond is made from carbon atoms just like diamond, but they are arranged in a different shape.

Imagine, a wurtzite boron nitride tipped drill. Read more at newscientist.com.