UK, 1826

Around March, 1826, one of the last ingots of Wollaston platinum was taken by the Glass Committee (authorized by the British government and under the aegis of the Royal Institution.)  Usselmann (PMR, 1983: Vol. 27, No. 4, p.179) cites Michael Faraday complaint on the high cost of Wollaston's Platinum, double the price of Wollaston's Platinum sold to Wm Cary.  However, it is not likely Wollaston overcharged the Royal Society (to which he was soon after granted membership) nor is it clear whether this cost included all labor. 

Therefore, the Platinum cost of the flint glass may be considered 'semi-manufactured' and nearly market-rate for the period.

March, 1826: 1 Troy Ounce Platinum (semi-mfg)  ~£ 1.80  (USD$ 8.86)
1826:  1 Troy Oz. Platinum (Paris producer retail) ~Fr 53.5 (USD$ 10.10)
1826:  1 Troy Oz. Platinum (est. semi-mfg) ~Fr 48. (USD$ 9.)

References to "Brazilian Platina" :

The US director of the Mint had previously noted Palladium in Brazilian Gold ingots in 1807, and "Brazilian platina" was mentioned by 1816 in US sources (Niles' Register.)  Platina was not so expensive then, however, and the quality of Brazilian ore was much lower. 

  

Professor Kemmerer's study dated from the Fall 1825 and was orginally published in January 1826.  This note was therefore added after publication, included with an issue or excerpt forwarded to the Paris Bulletin.    

Speaking in the past tense, the 'best quality ore from Brazil' (actually Antioquia, COLOMBIA) was sold in London at £ 1.05 (troy ounce?) :

Although the date is not certain,  given 

a) the December 1825 Paris Peak, and platina had sold at ~£ 0.3876 at Choco (September)

b)  the discovery, reporting and exploitation of the Antioquia mine by Fall 1826

c) time-lag for news between London-St. Petersburg

Kemmerer's Note probably refers to a London Price around Late Summer 1826, if the ore was indeed from the Antioquia mine.  If conflatingdifferent facts, this might be the dated 1825 Price High for London platina.  

In any case, Choco platina sold in London at 1/3rd the price by Early 1827.

c.1827

Citation: Bulletin des sciences naturelles et de géologie (1827)

1826: 1 Troy Oz platina (ore @ Choco)  = S$ 0.68 


1827: 1 Troy Oz. platina (Lond.:Choco, 85%, whols.)  = £ 0.3101 (USD$ 1.53)
c.1827: 1 Troy Oz. platina (Lond.: Ural, 75%, whols.)  = £ 0.2281 (USD$ 1.13)
 
Citation: Die metallischen rohstoffe, ihre lagerungsverhältniss und ihre wirtschaftliche bedeutung..., Vol. 16 (1962)

Heinrich Quiring?

"In London kostete ein kg columbianisches Rohplatin 1826 bis 1827 200 Schilling. Es wurde höher bewertet als das ..."

"Denn 1826/27 notierte in London russisches Rohplatin 146,65 s; columbianisches Rohplatin 199,4 s, Reinplatin 429,7 s je kg.  Paris nahm eine Zwischenstellung ein (Rohplatin 200 Frcs, Reinplatin 690 Frcs je kg)..."

1825 Great Britain Pattern Farthing Mule: obverse die belongs to the 1812 Pattern 9 Pence Bank Token (S3773A), and the reverse is from an 1825 Farthing.