The following is quoted from Wikepedia:
Carbon (from Latin: carbo “coal”) is a chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent-making for electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon is one of the few elements known since antiquity.
Carbon is the 15th most abundant element in the Earth’s crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon’s abundance, its unique diversity of organic compounds, and its unusual ability to form polymers at the temperatures commonly encountered on Earth enables this element to serve as a common element of all known life. It is the second most abundant element in the human body by mass (about 18.5%) after oxygen.
The atoms of carbon can bond together in different ways, termed allotropes of carbon. The best known are graphite, diamond and amorphous carbon. The physical properties of carbon vary widely with the allotropic form. For example, graphite is opaque and black while diamond is highly transparent. Graphite is soft enough to form a streak on paper, while diamond is the hardest naturally occurring material known. Grophite is a good electrical conductor whlile diamond has a low electrical conductivity. Under normal conditions, diamond carbon nanotubes, and graphene have the highest therman conductivities of all known materials. All carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form at standard temperature and pressure. They are chemically resistant and require high temperature to react even with oxygen.
Carbon forms a vast number of compounds, more than any other element, with almost ten million compounds described to date, and yet that number is but a fraction of the number of theoretically possible compounds under standard conditions. For this reason, carbon has often been referred to as the “king of the elements”.
To simplify the the above quote, the stuff to make diamonds with is the 15th most abundant element on Earth which is carbon. All it takes to make a diamond is the basic element, carbon, and a lot of heat and pressure. It does not take a lot of time either for diamonds have been made in literally a few hours, rather than the millions of years that is sometimes stated. And so it is that a diamond is made from the simplest and most common elements just as God has chosen the foolish things of this world to confound the wise. 1Corinthians 1:27 But God hath chosen the foolish things of the world to confound the wise; and God hath chosen the weak things of the world to confound the things which are mighty; All of us have the potential to become a jewel in the crown of God. All we need is the difficulty and pressures of this world to make us into a precious jewel for the Lord.
Just being a gem stone is not the same as being a cut stone that reflects the brilliance of the Light. It must be cut and polished in order for its beauty and glory to be seen. An uncut stone looks just like any other stone until it is cut. Only then are the beauty and dynamic of all that went into its creation, seen and radiate the Light from its creator. The glory is that of its Creator and not of the stone. Only He knows how much fire and how much pressure it takes to build all the faucets within to reflect the Light out for others to see the wonder of God’s working, for we are the workmanship of God.