Every piece of gravel is unique and millions of years old, too.

Indeed. The oldest things on earth are the hydrogen atoms. Literally all of them were formed in the first 3 minutes after the big bang. So all of them have the same age, billions of years old, down to a few seconds difference at most.

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rimunroe 5 days ago | parent [-]

> The oldest things on earth are the hydrogen atoms. Literally all of them were formed in the first 3 minutes after the big bang.

Stable hydrogen wasn't able to form until several hundreds of thousands of years after the Big Bang when the universe cooled sufficiently for electrons to bind to protons.

Even assuming you're counting lone protons as hydrogen atoms, it's still absolutely false. I don't know if that's true for the majority of protons in the universe, but there are mechanisms by which new protons are made all the time. Neutrons can turn into protons through beta decay, and high energy particle interactions like those involving cosmic rays can produce brand new protons. These processes can and do happen terrestrially.

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spwa4 5 days ago | parent [-]

> These processes can and do happen terrestrially.

... and at rates that mean that the amount of non-big-bang hydrogen is not even a trillionth of a trillionth of the total.

	▲	rimunroe 5 days ago \| parent [-]
		> the amount of non-big-bang hydrogen is not even a trillionth of a trillionth of the total. I didn't say it was a huge fraction of the total. You said "literally all of them" were from the Big Bang, which is just wrong. Plenty of other processes produce protons/hydrogen

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nwienert 5 days ago | parent | prev [-]

But not rare.

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cogman10 5 days ago | parent [-]

Diamonds aren't rare. Natural diamonds are artificially constrained to raise the price.

	▲	mensetmanusman 5 days ago \| parent [-]
		Large intact diamonds are rare. Diamond dust is not.