so what geological misconceptions have people had in the past and still have? well here is one
Reblogged from
Lounge of the Lab Lemming
Diamonds are not former coal. Coal is the organic-rich remains of terrestrial plant matter, and this
is younger than the oldest land plants, which are roughly 400 million
years old. Pb isotope studies of diamonds show that they are generally
between 2 and 2.8 billion years old, 5-7 times older than the oldest
land plants. Thus diamonds were already collecting their pensions by
the time the first coal beds were formed.
Secondly, they have different isotopic compositions. Plants, which fix CO
2 via photosynthesis, contain 2% less
13C
than the Earth’s mantle, while most diamonds have mantle carbon
isotopic composition. The light isotopic composition of coal is due to
the preferential uptake of
12C over
13C during photosynthesis. Diamonds, not being related to coal, never photosynthesized, and do not show this effect.
Thirdly,
metamorphic minerals have very different textures than hydrothermal
ones. Diamonds are thought to precipitate from a CO
2 fluid
when said fluid is reduced in the mantle. This allows big, low strain
crystals to form. Solid state phase transitions generally involve lots
of deformation and recrystallization. Were coal to be metamorphosed
into diamond, it would probably form a diamond rock with micron-scale
crystals. Impact diamonds have grainsizes that are micron to
sub-micron, and the source of the carbon is difficult to determine. But
they are tiny, and it is theoretically impossible for them to be more
than a few carats (they need to be small enough to cool off before the
shockwave dissipates, or they will revert to graphite).
Of
course, it is theoretically possible to synthesize diamonds from coal in
a lab. But this is unlikely to occur for several reasons. If the
diamonds are being grown in a traditional metal catalyst belt apparatus,
then a low sulphur carbon source should be used to prevent the nickel
catalyst from being attacked. If coal was sulphur free, then trout in
the Adirondacks would have nothing to complain about. In the case of
Chemical Vapor Deposition diamond, a gaseous source- usually methane- is
used. With either method, nitrogen from organic compounds in the coal
would impart a yellow-green color in the diamond due to the absorption
of the single N defect. So coal would be a poor source material for
synthetic diamond production.
To summarize: Diamonds are too
old to be squished coal, and even if they weren’t they contain the wrong
sort of carbon and form through different processes. Furthermore, coal
is a poor choice of precursor for synthetic diamond production, as
spectroscopic graphite is best for metal catalyst diamonds, and methane
is preferred for CVD.
To the government it is a tourist attraction, to the Luhya community living around it, it holds both cultural and spiritual significance. the community carried out rituals to avoid droughts and for cleansing ceremonies. In modern society too the rock holds religious significance as churches like Legio Maria and Rosary Church make pilgrimages to it.
