Presence in the cratonic lithosphere for long periods of time allows diamond crystals to grow larger.
The slightly misshapen octahedral shape of rough diamond crystal in matrix is typical of the mineral.
In terms of cultural value, diamond has long been the winner, but that may be set to change.
A new understanding of graphite’s inner structure has made it a source of wonder.
Cratonic roots extend into the mantle more than 125 miles (200 km) deep where pressure is high enough, but temperature cold enough, for diamond formation.
The first time I went to art class, the teacher, a man called Barrington, told us that everything we could see was made of atoms. And that if we could understand that, we could begin to be artists. He asked for questions, but all of us were struck dumb, wondering if we were in the right class.
Its lustrous faces also indicate that this crystal is from a primary deposit.
As I have noted previously, it’s a wonderful time to be a young-earth creationist.
The battle between dark, expressive, utilitarian graphite and sublime, cool, hard, glinting diamond has been raging since antiquity.
Scientists, using rigorous methods have established a process to eliminate this problem by calibrating radiocarbon dating results to items of a known age.
In this way, items of unknown age can be tested and an age determined to a reasonable degree of accuracy. More tomorrow where we explore the concept of isochron dating and how it neatly destroys most of the rest of these ‘issues’.
In the lithospheric mantle, the proper temperature and pressure are usually found in depths of 140-190 kilometers.
The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist.