# Japanese Gold Bars 999.9 **URL:** \ **Category:** Factual Questions\ **Created:** [November 2, 2019, 11:29am UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908 "2019-11-02T11:29:46Z")\ **Posts on this page:** 11\ **Page:** 3
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [November 4, 2019, 2:47pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/41 "2019-11-04T14:47:40Z")
Wait, what is 2.4K gold suppose to mean? I did not think that was a measurement of gold purity. It certainly can’t mean 10000% pure gold. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [November 4, 2019, 3:34pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/42 "2019-11-04T15:34:24Z")
“N karat” means N/24 parts gold. So 24 karat is 100% gold (within rounding errors), 18 karat is 18/24 gold and 2.4 karat would be 2.4/24 = 10% gold. I don’t know if anyone actually uses fractional karat measurements like that. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [November 4, 2019, 3:40pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/43 "2019-11-04T15:40:52Z")
> [@markn\_1](#): > > “N karat” means N/24 parts gold. So 24 karat is 100% gold (within rounding errors), 18 karat is 18/24 gold and 2.4 karat would be 2.4/24 = 10% gold. I don’t know if anyone actually uses fractional karat measurements like that. I understand that, but I don’t really think that 2.4 karat is an actual designation of purity unless it’s some kind of ‘white gold’ with a ridiculously small amount of gold in it. This must mean something else, I would assume it’s just a spurious decimal point in ‘24 karat’. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [November 4, 2019, 4:11pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/44 "2019-11-04T16:11:15Z")
> [@Johanna](#): > > Or you could just put it in a full tub of water, measure how much water it displaces, and calculate the density from there. _Eureka!_ Don’t forget, you have to run naked through the streets yelling that… ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [November 4, 2019, 4:18pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/45 "2019-11-04T16:18:11Z")
> [@Hermitian](#): > > So the reason is basically: “that is the way we in the gold community have always done it despite the fact that it doesn’t match the way anyone else expresses completeness.” > > You could make a case that “we have always done it that way” is not really a _good_ reason. Next you’re going to start complaining about the fact that an ounce of gold doesn’t weigh the same as an ounce of anything else. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [November 4, 2019, 4:23pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/46 "2019-11-04T16:23:06Z")
> [@markn\_1](#): > > Next you’re going to start complaining about the fact that an ounce of gold doesn’t weigh the same as an ounce of anything else. Well, it certainly weighs less than an ounce of feathers. ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [November 4, 2019, 4:23pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/47 "2019-11-04T16:23:18Z")
> [@Johanna](#): > > Or you could just put it in a full tub of water, measure how much water it displaces, and calculate the density from there. _Eureka!_ Easier with a smaller recipient, placed into another one which gets weighted before and after the spillover. > [@DesertDog](#): > > 24kt gold jewelry is (or at least was) popular in Asia as an easy way to carry around escape money in case things went pear-shaped. It does bend easily, though, more so than most people would want. Still is. Gold medals are a popular export from Spain to India and SE Asia (Spanish goldsmiths normally work with 24K). ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [November 4, 2019, 8:20pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/48 "2019-11-04T20:20:42Z")
Do you guys have me set to Ignore? 🙂 > [@septimus](#): > > As was [recently mentioned here at SDMB](https://boards.straightdope.com/sdmb/showpost.php?p=21850315&postcount=57), that story is mythical. Archimedes did determine the density of the crown, but he used a method far more clever — and more precise — than measuring water displacement: He weighed the crown with a balance scale while it was under water. While Google will show overwhelmingly and almost unanimously the usual tradition (begun by Vitruvius) that Archimedes measured displaced water, [Galileo thought otherwise](https://www.math.nyu.edu/~crorres/Archimedes/Crown/bilancetta.html). He figured Archimedes applied the full value of his buoyancy principle to measure the crown much more easily and accurately than any water measurement. (Some may assert that this would be a mighty clever method for Archimedes to devise. I note (a) Archimedes would hardly have celebrated ‘Eureka’ for the rather trivial solution, (b) Archimedes was certainly much cleverer than Galileo!) I don’t know if Cecil our Leader has ruled on the matter, but [several mathematical historians](https://www.thenakedscientists.com/articles/science-features/archimedes-original-naked-scientist) agree with Galileo. The matter may still be controversial, but Googling “Galileo” “Vitruvius” “balance” How did archimedes test the crown turns up many articles supporting Galileo’s theory, e.g. > **[Fact or Fiction?: Archimedes Coined the Term "Eureka!" in the Bath](https://www.scientificamerican.com/article/fact-or-fiction-archimede/)** > > The famed mathematician made many important scientific contributions. Was this exclamation really one of them? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [November 4, 2019, 10:27pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/49 "2019-11-04T22:27:32Z")
I have a 4-pound cylinder of tungsten, which easily fits in the hand and is a surprise every time I pick it up. I have equal sized cylinders of copper, iron, aluminum, and magnesium as well, and they all feel cheap and plasticky after handling the tungsten for a while. I did get it straight from China. Now I wonder if they cheated me and filled it with worthless gold instead. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [November 5, 2019, 2:46am UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/50 "2019-11-05T02:46:37Z")
Fun Fact: when platinum was first recognized by Europeans and before techniques existed to work it (pure platinum is much harder than gold or silver and it has a higher melting point than iron), its high density led many to worry that this “worthless” metal would make forging gold bars easier. ---
**Author:** ![MarvinKitFox](https://avatars.discourse-cdn.com/v4/letter/m/7ba0ec/32.png) [@MarvinKitFox](https://boards.straightdope.com/u/MarvinKitFox)\ **Post date:** [November 5, 2019, 4:46pm UTC](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908/51 "2019-11-05T16:46:48Z")
> [@Johanna](#): > > Or you could just put it in a full tub of water, measure how much water it displaces, and calculate the density from there. _Eureka!_ Oh rilly? I have a nice stash of [strike]gold-coated tungsten bars[/strike] REAL GOLD BARS to sell you. [Previous page](https://boards.straightdope.com/t/japanese-gold-bars-999-9/842908.md?page=2)