1700-1800, Europe: Platinum Prices Very Volatile

The price of platina had been less than Silver for some time, but rose in the late 1750s (shortly after its 'discovery' was announced.) Platina was first rendered malleable in Spain, then worked/sold in Paris by Chabaneau after 1780; he had taken a 19kg stockpile of ingots from the Spanish Mint.

c.1742?:

 Where 64 drachme = 1 once, ÷ 128 ; 

c.1757: 1 Troy Ounce Platinum = Fr 1,260.

Perhaps half-gros (~29.5 English Troy Grains) ? c.1757

Citation: The Quarterly journal of science and the arts, Vol. 3 By Royal Institution of Great Britain (1817), p.259

c.1760

In 1772, the Paris platina price was equivalent to ~5s 8d. per (UK) troy ounce.

1772 : 1 Troy Oz. platina (Paris Price, retail?) = Fr 6.10 (£ 0.28)

1772:

c.1774 After Buffon, Compt de Milly assumed gold had a specific density of
19.08397; converted (19.32 g/cm³), the specific denisty of Platinum shows the Buffon platina sample to be only 68.12% pure.

Dr. Lewis' Platinum sample appears to have been 79.52%

As cited from Lewis, via Parisian texts in Russia:

Apparently an editorial footnote from Engeström (c.1778?) or the later translator?:

Citation: An essay towards a system of mineralogy, Vol. 2;  Axel Fredrik Cronstedt, Gustav von Engstrom & John Hyacinth de Magellan (1788)




Quiring (1962) p. 73:
1778: "Die entschädigung betrug 10 pesetas für 1 pfund (460g) rohplatin. Daraus läßt sich eine Bewertung des rohplatins zu 18,5 Goldmark je kg. errechnen. Ein ähnlicher Preis ($4,4 je kg) wird fur 1788 angegeben."

1778: "The compensation was 10 pesetas for 1 Libra (460g) platina. From this we can extrapolate and calculate platina at to 18.5 goldmarks per kg. A similar price ($ 4.4 per kg) is indicated for 1788."

Quiring (1962) p. 73: Erroneous dates

"Englische kaufleute boten 1790 in dem platinausfuhrhafen Cartagena 25 Dollar fur 1kg Rohplatin. A. v. Humboldt, der 1819-20, Colombien bereiste, gibt den Preis ab wäsche mit 17 Dollar (71.37 Goldmark), in Paris mit 220-260 Frcs (42-50 Dollar) je kg an."

"English merchants offered in 1790 in the platinum export port Cartagena $ 25 for 1kg crude platinum. A. von Humboldt, who traveled 1819-20, Colombia, are the award from linen with $ 17 (71.37 Goldmark) in Paris with 220-260 francs (42-50 dollars) to each kg."

Counterfeit Platinum Coins were known from this period, although it cannot be certain this ungilded 8-Escudos example isn't a reproduction counterfeit, at 26.8 g. 

c.1800: suspect anecdote (1845 hindsight) but evidence of stockpiling

c.1815 history of platina: as a substitute for Gold, refined & manufactured Platinum could command nearly the same price (~75% ?)

Citation: The National register, Vol. 1, Dated 8/3/1816 p.365