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  • [ intro ]

  • Diamonds are iconic and often depicted as shiny colorless stones.

  • But it turns out diamonds are not always like that!

  • Sometimes, diamonds are green.

  • And stranger still, some of them get that way because of radiation.

  • ~

  • A diamond is just a particular arrangement of carbon atoms.

  • That arrangement is a regular, repeating pattern called lattice.

  • But when the lattice gets disrupted, diamonds can become different colors.

  • The origin of this strange phenomenon often begins underground.

  • Diamonds sometimes form next to naturally occurring radioactive ores

  • like ones that contain uranium or thorium.

  • Radioactive elements like these have an unstable nucleus at the heart of their atoms.

  • Over time they tend to decay into more stable elements and release energy

  • we call ionizing radiation in the process.

  • As these particles are released,

  • they can reach the lattice structure of the nearby diamond and collide with one of its

  • atoms.

  • And if they have enough energy,

  • they can knock a whole atom out of place!

  • The knockout atom then gets jammed between other atoms in the lattice,

  • creating a defect in the perfect carbon pattern.

  • So, you end up with a spot where there should be a carbon atom,

  • but there isn't one.

  • Misplacing a few carbon atoms here or there sounds like no big deal but,

  • it turns out they make all the difference when light bounces inside the crystal.

  • Diamonds are carefully cut so when light enters,

  • it gets reflected inside in just the right way for the light to escape back out,

  • giving it its sparkly white appearance.

  • But when the diamond has a defect the story is a little different.

  • The light gets absorbed by atoms around the lattice gap,

  • and sometimes in combination with other defects, instead of just being reflected.

  • That's because those nearby atoms aren't as tightly bound by the structure of the lattice

  • as they used to be.

  • So they can move around a little bit and absorb the energy from light waves as kinetic energy.

  • In particular, defects tend to absorb the red and blue parts of the visible spectrum.

  • Without red or blue light, the remaining light that gets reflected out of the diamond contains

  • proportionally more green light,

  • making them look green on the surface!

  • ~

  • Less than one in every thousand diamonds takes on the striking green color caused by natural

  • radiation, making them super rare.

  • And among green diamonds, some extra rare ones aren't green only on the surface;

  • the whole diamond is green!

  • A great example is the famous Dresden Green formed with natural radiation.

  • Why their whole body is green is still debated,

  • but it might come down to specific geological conditions and radiation sources.

  • With a little inspiration from nature, scientists have found ways of making diamonds green in

  • the lab.

  • Since the middle of the twentieth century,

  • laboratories have used artificial radiation sources like electron beams,

  • to turn ordinary diamonds into green ones.

  • This might be a little alarming because some green diamonds might be radioactive,

  • which might seem a little dangerous.

  • But in the US, the process of irradiating gemstones this way is tightly regulated.

  • So that even if the diamonds become radioactive themselves,

  • they're held in safe storage until their radioactivity drops to a safe level.

  • So, if you have the good luck of receiving a green diamond,

  • you can rest easy that it won't do any harm to you if you wear it.

  • Except, maybe, making your friends green with envy.

  • Thanks for watching this episode of SciShow!

  • We've made thousands of educational videos over the years,

  • and we've been able to offer them for free because of our patrons on Patreon.

  • So, to all of our patrons, thank you for what you do to make SciShow happen.

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B1 中級 美國腔

辐射是绿色钻石最好的朋友(Radiation Is a Green Diamond’s Best Friend)

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    joey joey 發佈於 2021 年 06 月 30 日