Talk:Cullinan Diamond

@Cherkash: Re [1], the fifth biggest gem-quality diamond ever found has just been discovered at Letšeng mine in Lesotho. It weighs 910 carats – about a third of the 3,106-carat Cullinan diamond's weight – and is valued at US$40 million.[2] The Lesedi La Rona diamond found at Karowe mine, Botswana, in 2015, weighs 1,109 carats and sold in September 2017 for US$53 million. This inflation-adjusted value of £14.9 million for the rough Cullinan is, like I said, a joke. Precious metals and diamonds are global commodities whose value rises and falls independently of any one country's GDP or CPI. Firebrace (talk) 14:06, 15 January 2018 (UTC)Reply

That's very interesting because I think the template used to say it was equal to £138 million for 3106 carats (£44,000 per carat), which is much nearer to the modern values: $40 million for 910 carats ($44,000 per carat) and $53 million for 1109 carats ($48,000 per carat). But the old template doesn't work anymore. Celia Homeford (talk) 14:27, 15 January 2018 (UTC)Reply

I think it was £88 million, which is equal to US$121 million ($38,956 per carat). It was inaccurate, but still more realistic than £14.5 m (US$20 m). The old nominal GDP per capita template has been nominated for deletion following a discussion at WP:INFLATION. Firebrace (talk) 14:45, 15 January 2018 (UTC)Reply

Celia Homeford, Firebrace. This is Economics 101. Basically, two things explain it:

1. Market value of any given product (aka good, aka commodity) at any given time (and across times) is usually subject to very different fluctuations than the value of money itself. The value of money itself is adjusted for inflation to achieve money-equivalence across times – so adjusting £150K in 1907 £'s (which is the nominal value of the price paid back then – which in itself might not have necessarily been an open-market value, but let's leave this aside for now) gives £15 million in modern £ terms (also known as real value of the 1907 £150K in 2016 £ terms). This is very non-controversial in Economics.
2. The fact that the "market valuation" of this diamond seems to be higher today than the inflation-adjusted value of money (pegged at about £15 million by a standard inflation-adjustment procedure), simply means that diamond prices (especially of the rarest diamonds) have inflated much more in the intervening 100+ years than the average prices of most other goods & services. It means just this. Nothing more, nothing less.

(Now, a technical point.) The old template was incorrect – it didn't do inflation adjustment, but did something else completely. It was a technical mistake to introduce that erroneous adjustment under the covers of Template:Inflation and it's been fixed now. So no reason to refer to it as being "more correct": it's not. It has nothing to do with neither diamond-prices inflation, nor with money (£) inflation. cherkash (talk) 20:54, 15 January 2018 (UTC)Reply

Laypeople reading this article are going to think you can buy a 3,106-carat diamond today for £15 million. Firebrace (talk) 21:17, 15 January 2018 (UTC)Reply

That may or may not be so. But if you think so, then please re-phrase in a way that makes it abundantly clear we are talking about the value of money (£), and not the market prices of diamonds. I tried to make it clearer by my placement of the "equivalent to..." parentheses and phrasing it in a certain way. But feel free to make an even stronger and more elaborate statement. But I'm of a strong opinion that skipping this conversion altogether makes no sense: no one knows the value-of-money equivalence (aka inflation adjustment) by heart, so mentioning the 1907 "nominal value" alone helps no one (neither a lay reader, nor a more sophisticated one). cherkash (talk) 21:26, 15 January 2018 (UTC)Reply

Thing is, none of the many reliable sources that I have read on this topic provide a modern-day equivalent for the £150k. It seems a bit WP:OR to include such an equivalent here when no other publisher has seen fit to do so... Firebrace (talk) 21:36, 15 January 2018 (UTC)Reply

It's a pretty standard adjustment and it's done all over Wikipedia. If you have a particular objection to the methodology of inflation adjustment, or to its widespread (and non-controversial) use, you could take it up at the Village Pump: given the scope of its use this is likely the most appropriate place to do it – more so than at the template's own Talk page. Moreover, the reference for this adjustment is stated right there and then (using Template:Inflation-fn) – so it's not an OR at all. If you have the beef with the actual series used for this adjustment and think it's either incorrect or have a suggestion of a better source, then this (more technical) issue should be taken up at the Template talk:Inflation. cherkash (talk) 22:30, 15 January 2018 (UTC)Reply

The colour portrait of Queen Mary used in the Cullinan Diamond article to illustrate the Cullinan 1 & II is incorrect. If you blow the image up, she is wearing a slightly larger brooch made up of similar shapes but many diamonds. The Cullinan I & II as a brooch is a brooch made up of the third and fourth largest single stone, natural diamonds, in the world. I have never seen the brooch the Queen is wearing in this portrait here. I think you will find that the Cullinan III is actually hanging as a pendant on her necklace, and is not being worn here as "Grannies' chips", the Royal Family's nickname for the Cullinan III and IV as a brooch which our Queen still wears. — Preceding unsigned comment added by 122.149.119.164 (talk) 01:53, 16 September 2019 (UTC)Reply

PS which makes the entry for Cullinan I incorrect. The brooch from the large Cullinan stones is made up of III & IV, not Cullinan I

Cullinans I and II can be made into a brooch, and as the article says Queen Mary 'often wore it like this'. The brooch in the picture looks like that brooch. Yes, she is wearing Cullinan III as a pendant, and also IV on her crown. This is again explained in the article text and in the caption. Celia Homeford (talk) 11:22, 16 September 2019 (UTC)Reply

Hmm. No, as we see from this picture it's definitely Cullinans I and II. Firebrace (talk) 12:32, 21 September 2019 (UTC)Reply