According to evolutionists and geologists, diamonds were formed about 1 to 3 billion years ago, much earlier than any known record of Earth’s first land plants. Coal is formed from the dead remains of vegetation like trees and other plants. The formation of coal takes millions of years and can be traced back 300 to 400 million years, but not a billion years.
Coal is an amorphous form of carbon and at the most can change its
chemical composition and transform into its nearly purest form which
is Graphite, but not diamond. The conversion of coal into diamond is
almost impossible due to its impurities and the fact that coal is
rarely found at depths greater than two miles which is not conducive
to the formation of diamonds.
Natural diamonds require depths of 87 to 120 miles in the Earth’s
mantle, very high temperatures, and resulting pressure that exists
at those depths to form. Unlike other gems which are formed by a
combination of elements, diamonds are made up of one single element,
Carbon. Carbon-containing minerals present in the Earth at those
depths, crystallize to form diamonds, because of the immense
pressure together with the heat from molten magma.
The diamond crystals, along with other minerals are transported to
the earth's surface during deep-source volcanic eruptions in the
magma. This is quite a rare occurrence as diamonds are formed at
depths usually 3 to 4 times deeper than normal volcanoes originate.
Diamonds color is influenced by impurities and can be blue (boron),
yellow (nitrogen), brown (lattice defects), green (radiation
exposure), purple, pink, orange, red, and grades of those colors.
Red diamonds are the rarest and most exotic diamonds. They are also
the most expensive. Here are examples of a red and orange diamond.
When this magma cools, it forms igneous rocks known as kimberlites
and lamproites, used as an indicator by geologists that diamonds may
be found in the area. The Kimberlites form narrow pipe shaped
fissures which are also referred to as diamond pipes. Many of the
pipes are also rich sources of garnets. The most prominent
kimberlites are located in South and Central Africa, which
contribute almost half of the natural diamonds mined in the World.
Over 500 kimberlite deposits have also been found in Northern
Africa, Russia, Australia, and Canada are the largest diamond
producing countries. BTW - Diamonds are not in short supply and are a terrible investment because there is no aftermarket.