[mitchty]

1. Manmade compressed and heated carbon is as passable to the next generation as the geologic kind. What is the issue here exactly? If anything its more awesome we can make our own and not rely on geological processes.

2. Why do I need to insure carbon? Its... carbon, super abundant, element 6. Present after the first generation of stars exploded in the universe. Are you investing in diamonds? They almost never go up in price, try reselling one or look at resale value before you worry about insurance.

3. What is the goal of this question? To show the Jones' that you have too much money and can pay the danegeld for authenticity? Before the 1940's diamonds weren't even a thing in marriage. If you could reproduce the Mona Lisa perfectly, would you pay N times as much for the original? Even if it was impossible to tell? Why is that so important?

4. Diamonds are already used for industrial uses, their "rarity" (they're not rare) is all due to a cartel named de beers controlling supply. They're common as hell, as noted, they're just compressed and heated carbon. These industrial uses are why we have these manmade diamonds in the first place. They're better than the originals as they're more consistent without imperfections. Just like modern steel would produce a katana infinitely better than folded crappy steel that the originals were trying to overcome.

[y4mi]

I was with you until the last point...

> Just like modern steel would produce a katana infinitely better than folded crappy steel that the originals were trying to overcome

That's not an undisputed fact.

There has been a lot back and forth about the lost knowledge of previous generations and the romans supposedly used a superior cement which we can no longer replicate.

but to stay closer to your example: while the smelting of the metal has seen a lot of study, that doesn't mean that we're able to produce a superior katana.

You also need the smithing -- and need to figure out how the metal should be. That's of course possible, but hasn't really seen much study. So while we could theoretically produce an infinitely better katana -- thats not practical because of the money investment to figure out what that actually means.

Most enthusiast say that current katanas are at best on par with the old ones, often sub-par.

[mitchty]

> That's not an undisputed fact.

We can produce steels today with much better metallurgical properties by design. Japanese steel at the time used the folding technique to overcome low carbon content. Thats all my point entailed. And as to what enthusiasts think, all I can counter with is the audiophile community. I wouldn't take their view without some salt especially without some comprehensive analysis. Steel from Spain at the time was also vastly superior to the steel being used in Japan.

Ref: https://www.omicsonline.org/open-access/mechanical-propertie...

Quote: The material and mechanical properties of samurai swords (Japanese swords), made using a traditional steelmaking technology (tatara), are investigated experimentally. The quality of these swords appears to be low because of the presence of a large number of inclusions, including oxide- and phosphorus-based structures; however, their mechanical properties are relatively good because of their fine-grained structure and high residual stress.

endquote

Also, take the metallurgical properties of turbine blades, there are alloys we can only recently produce based on analysis of bonds between the atoms. While its posssible a past civilization could have come up with these alloys, the neither needed them, and lacked the requisite knowledge to make them.

And the roman cement was largely a product of materials. Aka volcanic ash. We lost it only in that the inputs were largely lost. But this all digresses mostly into arguing analogies which is a bit of a rat hole.

[Steve44]

> the romans supposedly used a superior cement which we can no longer replicate.

I read a few years ago the 'secret' had been discovered and it was to do with volcanic ash which made it self healing.

Doing a quick search there seems to be a lot of articles from 2014 about this so possibly that what when the research was published.

https://archserve.id.ucsb.edu/courses/arthistory/152k/concre...

https://www.ibtimes.co.uk/why-pantheon-has-not-crumbled-roma...

http://www.pnas.org/content/early/2014/12/10/1417456111

[dvfjsdhgfv]

> the romans supposedly used a superior cement which we can no longer replicate.

Could you recommend a related source I could read more about it from? It seems not that complicated to do a chemical analysis of the cement still existing in many Roman constructions.

[y4mi]

it seems my information was outdated...

https://news.ycombinator.com/item?id=17186124