Diamond is the hardest natural material known to man. It’s so hard and it cannot be scratched even by other diamonds! Diamonds are formed deep underground at high pressure and temperature, usually 90-120 km below the surface.

Diamonds are normally carried towards the Earth’s surface by a volcanic eruption or other similar processes that bring them up under scorching conditions. Diamonds are also mined from specific surface exposures where a geologist can identify a diamond-bearing kimberlite “pipe.” A volcanic pipe is the throat of a volcano that has become inactive. Such rock formations were formed by violent eruptions which brought diamonds to the Earth’s surface and erupted them in place.

Smaller diamonds may be formed by meteorite impact. The heat and pressure of the impact can sometimes produce tiny diamonds, usually only seen under a microscope. Diamonds are also found in meteorites that have fallen to Earth.

Diamonds typically contain impurities such as boron, nitrogen, or hydrogen. But the most common impurity is graphite, another form of pure carbon. Graphite is a softer material and can form twinned crystals with diamonds called “kames.” Diamonds containing graphite may be artificially converted into an artificial material identical to a natural diamond but have a higher clarity using a process called “diamond upgrading.”

The hardest naturally-occurring substance known on Earth is a “nanotwinned” form of diamond known as lonsdaleite, composed of carbon hexagons arranged in a variation of the cubic crystal system called a hexagonal diamond.

Pieces of jewelry with large diamonds are usually set in silver or gold because of the softness of pure diamond. A good substitute for this purpose is white zircon, which is similar to diamond but doesn’t have its color. It’s often mistaken for diamond by those who don’t know gemstones well.

The most giant diamond is the 3,106 carat (621.35 g) Cullinan Diamond. The largest cut gem-quality diamond is the 545.67 carats (109.13 g) Golden Jubilee Diamond which was cut from the 995.4 metric tons (1,097 short tons) Cullinan Diamond – the biggest rough diamond ever found. The 3,106 carats (621.35 g) Cullinan Diamond was found in 1905 at the Premier Mine near Pretoria, South Africa.

The largest polished gem-quality diamonds, such as Golden Jubilee and Cullinan, are exceptional because they are extensive and high-quality. A “fancy” diamond is any diamond that doesn’t fall into one of the categories below. The term “fancy” refers to shape, color, clarity, and cutting quality – not the value or weight.

The three most valued colors for fancy diamonds are pink diamonds, blue diamonds, and yellow diamonds – with pink being the rarest color. The most desired color in a fancy diamond is the blue diamond.

Diamonds with different colors also have different values depending on how rare their colors are and how much customers are willing to pay for them. Pear-shaped diamonds, in which the pointed end is in the direction of the setting of a ring, can make a smaller diamond look larger when set as earrings, brooches, or pendants.

Blue diamonds are created when other diamond colors are exposed to extremely high pressure deep in the Earth. The extreme pressure changes the structure of the diamond’s carbon atoms into a different crystal form, which causes blue coloration to be seen in some diamonds.

Fancy-colored diamonds don’t have as many colors as those in the blue to the green range, making them harder and more expensive to produce.