How can Zircon be used to record data for generations of life forms?


  • Must be able to store the data with little to no loss of it, for a least 541 million years
  • The data in the zircon must be only accessible to civilization that are at least as advanced as 16th century Europe
  • Must be stored very compactly
  • 3
    $\begingroup$ You make a gem out of that zircon. Those guys have some pretty good memory. $\endgroup$ Sep 17, 2018 at 22:11
  • 3
    $\begingroup$ What form of data? Text? Numbers? Images? Who is recording the data? Who is expected to read the data and how do they know there is data in the zircon? $\endgroup$
    – Gimelist
    Sep 17, 2018 at 22:21
  • 1
    $\begingroup$ "Able to store the data with little to no loss of it, for a least 541 million years": how is this data support stored for 541 million years? There are not that many places on Earth where 500 million old rocks are exposed to the surface. $\endgroup$
    – AlexP
    Sep 17, 2018 at 22:29
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    $\begingroup$ "The zircon will be passed down from civilization to civilization over 541 million years": that is not believable. The average duration of a mammalian species is about 2 million years. Half a billion years is a long time. Continents are born and destroyed over such a timespan. Anyway, if the zircon tablets are kept carefully, then they can simply carry carved inscriptions. $\endgroup$
    – AlexP
    Sep 17, 2018 at 22:43
  • 1
    $\begingroup$ @Shadowzee Okay changed it to science based $\endgroup$
    – Amoeba
    Sep 18, 2018 at 1:47

6 Answers 6


This question is rather similar in nature to the task undertaken by the metrologists who take care of the Kilogram Prototype, known by its French initials as the IPK.

The IPK is currently the definition of the kilogram. It is a block of platinum iridium stored in French vaults in the International Bureau of Weights and Measures. If the IPK degrades ever so slightly, our entire system of masses suffers. Indeed there is an issue for metrologists here: the IPK and its sister prototypes have strayed from eachother, by 10 ug in the last 100 years. That's 0.000001% over 100 years. If this continues for 5,210,000 times that long, that's about 1/4 of the whole mass of the IPK!

It's believed the main cause of mass loss for the IPK is cleaning. So the number one rule for this zirconium object is that it needs to be handled less than the IPK is. The IPK is hardly handled at all. It is brought out once every 40 years to be compared to its sisters, so we need this object to be brought out far less often. I'd recommend it not be brought out any more often than once every few millennium. At all other times, it should be stored under a similarly high level of protection as the IPK: several evacuated bell jars are recommended.


I would recommend a tremendously long-lasting glass for the inner jars. Quartz glass comes to mind. There should be a very elaborate ritual for changing the innermost jars (as they will age over time).

I would also recommend the Zircon be rather gigantic. While I could not find numbers for the diffusion rate of elements within a zircon crystal, just because you can date a crystal 4 billion years old does not mean that the atoms in that crystal have not moved around to a low-energy structure. On that timescale, fractures are known to mend themselves! As such, you should probably rely on great big letters, and not say too much. A mere "Sorry for the inconvenience" on the side of a mountain is probably ideal.

From there, you can start the real challenge: how do you maintain a language sufficiently for 521 million years such that the individuals of this civilization understand the meaning of the symbols engraved. Fîf−hund tôgêare for−brêdan spr¯æc fullfremed weargbr¯æde synderlicnes!. And if you understood that last sentence, you would know that just five hundred years is more than enough to make a language incomprehensible!

  • 1
    $\begingroup$ Side note: "If this continues for 5,210,000 times that long, that's about 1/4 of the whole mass of the IPK!" That's why people are looking for an absolute definition of the kilogram; AFAIK there is building consensus to provide an exact value for the Plank constant (at 6.62607015E−34 J⋅s), which would link the kilogram to the metre and the second (which already have absolute definitions). $\endgroup$
    – AlexP
    Sep 18, 2018 at 6:30
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    $\begingroup$ @AlexP Yup. I've heard that the proposal to make it based on Avagadro's number has won, and will find its way into the next revision! $\endgroup$
    – Cort Ammon
    Sep 18, 2018 at 14:57
  • $\begingroup$ Since the IPK isn't the definition any more, you might want to update this. $\endgroup$
    – Spencer
    Dec 17, 2021 at 19:43

Zircon is an excellent choice. If you can find a way to encode information in it, it is datable and you can get a specific point in time in which it was formed. Ages obtained from zircon cannot be forged (*), and are highly reliable. Contrary to what people said earlier in other answers or comments, zircon is an extremely durable material. Zircon can survive millions of years of weathering, burial, remelting into magmas, volcanic eruptions, whatever. If your "keepers-of-the-zircon" will put minimal effort into preserving it (basically, do not touch it) it can last forever. Even if people actually touch it millions of times, nothing will happen to it.

Challenge 1 - putting data into the zircon

Since you want a 16th century civilisation to understand it, it can't be digital, or something that requires a computer to decode. Language changes over time, so words or letters are not a good candidate. We can't even understand things that are hundreds or thousands of years old, unless we have some luck in finding a code (e.g. the Rosetta stone). In other cases, we simply can't read it (e.g. Voynich manuscript).

Your best bet would probably be 3D figures. Our current technology allows for two excellent methods, both of which give very detailed 3D images:

  1. Laser engraving. You probably know these from souvenir shops. Here's one:

enter image description here

  1. 3D printing. This allows you to use different materials or colour in your image.

Note that method 1 requires you to have a zircon to engrave into, and method 2 requires you to grow the zircon around what you printed. The material you're using will have to be thermally resistant so it will survive the zircon growing process (see next).

Challenge 2 - getting the zircon

You will not want to use natural zircons. Here's why:

  1. Zircons big enough are extremely rare.
  2. If you do find zircons big enough, they're more likely to be opaque or very dark and you will hardly see anything through them.
  3. Natural zircons will already have some age, and if you want to combine 1 and 2 with a very young zircon (younger than let's say, 1 million years), the chances of finding them are close to zero.
  4. This will not work if you want to use 3D printing. You have to grow the zircon around what you printed.

Your solution is growing your own zircon. This will ensure the age of the zircon is zero at formation, and you will get a nice translucent crystal you can put stuff in for everyone to see. You can use several methods, like chemical vapour deposition, or flux melt single crystal growth, or any other crystal growing method your advanced civilisation can come up with.

Challenge 3 - getting your 16th century civilisation to read it

Easy. Use a magnifying glass.


Challenge 4 - showing that it's genuine.

This is where it gets interesting. Your 16th century civilisation will probably not be able to understand what the crystal is, or how to judge whether it's real or not. As far as they know, it could be some form of special glass, or any other crystal. Quartz? Topaz? Could be anything. It took a few hundreds years for people to actually settle on what zircon is and how to call it, finally settled in the 18th century.

In the late 20th century, technology advanced sufficiently to be able to precisely date zircons, so the age will only become apparent to generations later than your 16th century folk. Now, many people will (rightfully) claim that it is fake. Because seeing an artificial-looking zircon with shapes and stuff in it, looks like something made recently, in the 20th or 21st centuries. Whilst in principle it's not possible to fake zircon ages, it can actually be done in some circumstances.

Dating zircons is based on the fact that U and Th share the same chemical properties as Zr, so when zircon is crystallising it can host some U and Th in the crystal structure. Eventually they decay to Pb, and Pb is extremely different to Zr so the assumption that none is initially present in the zircon. However, there are some conditions that allow for Pb to be introduced to the crystal structure.

To make it easier to prove that the zircon is genuine, you need to put things in the zircon which are incompatible with the other things that let Pb in. One of them would be some rare earth elements, as their chemical pattern allows determination of oxidation state (one of the ways to put Pb in).

  • $\begingroup$ I think you dismiss "Challenge 3" too easily. There should be obvious "breadcrumbs" that lead to the data. The storage object should be marked with an image that is easily visible with the naked eye. Next to the first image there should be a second smaller image, followed by a third that is barely perceivable, then the data. $\endgroup$
    – Skek Tek
    Oct 1, 2018 at 12:57
  • $\begingroup$ Challenge 1: You can easily include a primer (your own custom Rosetta stone) that would allow you to build a language and convey ideas more precisely. $\endgroup$
    – Skek Tek
    Oct 1, 2018 at 13:02

So your crystal needs to last 541 million years while being passed from generation to generation. The surface of it will likely be touched, rubbed and eroded over such a long time, so storing data on the surface isn't going to work out too well. 541 million years is going to be 5 million generations of humans (more like 10 million) which is 5 million passes from hand to hand and any sort of sharp edges will erode and smooth out. You also don't want it to be damaged, so instead you want to put the data inside the crystal.

I'm not sure how feasible this is. Your going to need to use a bunch of computer programs and lasers to get it to work. Basically you can use a laser to create a small imperfection in the crystal. Like a CD really, but on 3 planes (x,y,z so they don't interfere with each other too much when being read back) and with tiny cracks instead of burn marks. Its like those glass/crystal cubes you can buy at a souvenir store. So now you have data embedded in the crystal but its not going to be readable to people in the 16th century. They are going to need a solid understanding on the encoding method you used (usually binary and a ton of compression on top of it) or have a identifiable pattern.

So instead, you could be creating small imperfections in the shape of letters or pictures. This way they could be visible and hence interpreted by a person looking at it under a lens. Now as it gets small and more compact, this becomes harder and harder. The best way, would be if they could hold a candle close to the crystal, and the shadow of the words/images appear on a wall a fair distance away. This combined with a magnifying lens would allow you to get a ton of information into a generally small space.

If you could, you should also make it appear different when the light is applied from a different angel. Sort of like those art works that can be viewed in two different directions to form two different words. You could easily get 3 (X,Y,Z as I said before), but you can probably fit 1 or 2 more planes if you don't stick to the 3 planes and try something based off of reflections or non orthogonal planes.

You can play around with offsets and stacking planes and the darkness of the shadow formed by an imperfection, but any data stored in it should be fairly safe as long as the stone itself hasn't been destroyed or clouded over.


Not sure where 541 million came from; not a round number. But, what the heck?


Your zircons either have to be small enough to be usable as gems, or they have to large enough to be immobile, or nearly so. I would suggest the latter -- make them squat obelisks 10 feet high or so.


You need several layers of data at different resolutions.

  • Top level: It needs to be beautiful, captivating, mysterious.
  • Second level. Illustrations of useful information, including basic optics and how to make a microscope. This level is also a rosetta stone, possibly using basic chemistry and the periodic table as the Omnilingual (See the short story by that name by H. Beam Piper) Second level illustrations reveal more detail when examined with a magnifying glass, and even more with a jewelers loupe.
  • Third level. A microscopic history of technology, culminating in lasers and holography.
  • Fourth level. Holographic data storage.

The levels can be intermixed: E.g. The top level illustration can be made of small -- need a magnifying glass -- illustrations. Illustrations can have hologram data embedded in frames next to them with references in the data.

Encoding should start a substantial distance into the zircon, so that you can have a fair amount of wear on the surface without destroying data.

The illustrations should not be something that looks like silver or gold. Barbarians will try to take it apart, and while zircon is tough it's not indestructible.

Obelisks are mass produced, and placed in geologically stable spots. Not all obelisks are identical, but core information is repeated often. Discovering a new obelisk is always potentially revealing.

Going the other way in size, look at making zircon poker chips. Each one has only the top levels of data. Each points to the tech just to survive better, and eventually to get a level of tech that gives them access to the hologram data storage of the obelisks.


There is some merit in making them hollow, as a light object is harder to bury. OTOH a floating object is easier to smash.

Half a billion years is daunting. Look how uncommon fossils of that age are compared to the number or original critters there were.

To give you an idea of the magnitude of the task: The rocky mountains are mostly in the 3-8 thousand feet above the surrounding plain. But in the last 40 million years or so there has been some 50,000 feet of erosion from them. They are big because they are being pushed up faster than they are being worn down.

Hawaii with it's peaks is only a few million years old. Make a list of 100 million year old islands....

Why 16th century? Technology is a true blink of an eye by your scale of events.

Put the zircons on the moon. THAT's stable. Or in orbit around Pluto, or around Saturn, but outside the rings, as the rings aren't a long term (a few million years) feature. Putting a few on each major asteroid may work too.

Consider making packages of zircon poker chips embedded in ceramic foam, of sufficiently low density that the package would survive re-entry at 50 km/s (This is typical cometary debris velocity.)

Somewhere in the oort cloud you have a self repairing machine that creates and dispatches ceramic marshmallow packages of zircon poker chips. Package density is light. You want the packages to float and get stranded on land. The ceramic eventually degrades, and exposes the pile of chips to the view.

This might have a chance of surviving a half billion years. The Oort cloud is a lot more benign, if you can lick the design issues of working at temps under 10 K. Machinery might only have to wake up for a few years every million years, make and send off it's packet, then wake up again to make sure it got delivered. One of your characters can be the AI that runs the poker chip assembly line.

If you are willing to have active intervention, a lunar based AI could monitor Earth and move obelisks around as needed. In the early parts of the story, the obelisks are accepted. Later, when they get reasonable theories of geology they see that the placement of the Knowledge Stones is too non-random. Why should so many be located and river junctions, good harbours, and easy mountain passes.


You simply can't make something that will be reliably preserved for that amount of time. the ancient zircons we have a small lucky number of millions. Atoms shift over billions of years, even in solid, so your data will likely be lost even if the crystal survives. see fission track dating, for one of the ways this occurs.

Zircon exposed to the air will also undergo chemical alteration over that span of time.

Worse yet, passing it from civilization to civilization is probably hr best way to guarantee it is damaged or destroyed since the civilization won't see it as especially valuable until it can read it. Many will also be temped to destroy it out of conflict, religious fervor, or other stupidity intelligence creatures engage in.

Finally you have the issue that the daa won't be readable just becasue the civilizations will not share languages in common. so even is you used of massive slabs of zircon and used large carved letters, and somehow convinced civilizations to take care of them, no one could read them.

If you want something that can survive and be read you need a mechanical AI that can repair itself and learn new languages. there is nothing that can reliably survive, passively, in an atmosphere for that amount of time. You need something that can take care of itself.

  • $\begingroup$ 5D Superman optical storage crystals could last as long as the universe at room temperature. en.wikipedia.org/wiki/5D_optical_data_storage $\endgroup$
    – Pyrania
    Oct 3, 2018 at 19:39
  • $\begingroup$ @Pyrania the testing for that really only accounted for temprature, many many other things are in play in the real world. $\endgroup$
    – John
    Oct 3, 2018 at 23:13

Laser encoding relies on breaking, or at least disrupting, the lattice bonds in the crystal substrate the code is being written into. Those lattice bonds are subject to further disrupting from cosmic rays, and other radiation, leading to data corruption. More importantly they also anneal over time, the crystal collapses back from the stressed state that the warped lattice has created and reforms the disrupted bonds erasing the data created by them. To keep data in anything like a lasting fashion over geological time you'd actually need to use a preparation of two distinct and chemically individuated minerals. You create a massive Zircon in which is encoded, using whatever recording and coding method you think is appropriate, the message in a different durable material. As an example you could use Diamond "letters" in a high contrast, and naturally rare, Green Zircon body, Carbon has a low diffusion rate in Zircon and is tightly held in the diamond lattice as well. Both minerals have incredible longevity as long as deliberate attempts at destruction are ruled out. An even better combination might be to encase Lead "letters" in Zircon; as Zircon doesn't take up Lead once it has fully crystallised, (this is the reason the Uranium-Lead dating series for Zircon is so accurate) the lettering on the tablet wouldn't be subject to diffusion into the Zircon body. Lead will take on a white surface oxide but doesn't generally weather very much in nature and if sealed entirely into the zircon won't even be subject to that degree of surface weathering.


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