diamonds.
diamonds have remarkable physical qualities…the most tightly compressed form of carbon. strong covalent bonding between the atoms. more than 99.9% carbon. hardest substance with the highest thermal conductivity. they are formed under intense heat and pressure deep within the earth.. some 150 kms beneath the surface.. in the earth’s mantle..to which they rise in the medium of magma ..molten rock in volcanic activity. its as if the core of our marvellous planet is scattered with diamonds gracing the logos--planetary and solar.. (some stars are said to have a diamond core. some diamonds are said to originate from space.)
on the surface of earth though, they are rare.
because it is so dense, light travels slowly through it.. causing remarkable optical characteristics..
prized as jewels since antiquity it is in the past few centuries that they have become popular. their value is enhanced by skilful shaping.. the diamond is given faces. or faceted by engraving a mark/ line with a diamond pointed tool and applying the correct pressure. it is not a rough trade. the planning and execution can take years. they are hard and expensive.
up till the mid 18th century India alluvial deposits were the source. since then they come from mostly brazil, Africa and Australia.
the art of producing artificial diamonds took a while to emerge. but not from want of trying.
that the diamond consisted of carbon was recognised in expiriments carried out in france in the late 1700s.. subsequently it was recognised that the other form of carbon in mineral form .. graphite, differed in its structure.. it needed to be placed under pressure.
a growing body of literature developed on what didn’t work..
the science of high pressure developed gradually through the 19th century.
in 1913 with the development of thermodynamics, xrays were used to determine the atomic structure of diamonds.
the structure of a diamond is the diamond (tetrahedral) lattice. we know today that it is an allotrope of carbon.. ie. it is carbon with its own way of bonding at an atomic level.....
it was increasingly obvious that pressure was the key to diamond formation.
in time synthetic diamonds were made but their use is mainly in industry.
drill bits.. abrasives. possible uses include semiconductor for microchips. or use as a heat sink in electronics.
the way to test a real diamond is with thermal conductivity.. spectroscopy , luminescence and microscopy can determine it sorigin. there are screening machines that do it.
its interesting. .. I haven’t scratched the surface really..
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