USA, 1870: Codman & Shurtleff's Catalogue and Ore Low?

1870: 1 Troy Ounce Platinum (Trade: Semi-mfg) = $ 6. - 8. (USD$ 6.89 - 9.19)
1870: 1 Troy Oz. Gold (24k, whols.) ~ $ 24. (USD$ 27.58) 
1870: 1 Troy Oz. Silver ("pure," whols.) ~ $ 1.80 (USD$ 2.07)
  

In Codman & Shurtleff's Catalogue of dental furniture, instruments, implements, and materials, : for sale by Codman & Shurtleff, manufactures, importers, wholesale and retail dealers, 13 & 15 Tremont Street, Boston (1870):

p.59: Mechanical Dentistry - The price of gold, silver and platinum is in gold; premium to be added.
Gold plate 22 carats fine .... per dwt. $1.10 ($ 22./oz troy; USD$ 25.28)
Pure Silver .... per oz. 1.80
Platinum Plate/Wire ... 6.
{Platinum} Fine Wire; Foil for chemical purposes .... 8.
Zinc ... per lb.   .15

1870: 1  Troy Oz. Platinum (Imported) =  $ 4.67 (USD$ 5.36)

1870: 1 Troy Oz. platina (London, bulk) ~ £ 0.90 (USD$ 5.03)

1870: 1  Troy Ounce platina (Paris, bulk) ~  Fr  ;


1871 :1 Troy Oz. Platinum (refined, imported) = $ 5.50 - 15. ($ 6.32 - 17.24)

Citation: Census bulletin: no. 210 special, Volume 1, By US Census Office (1902) p.10

US Imports:



Counterfeit Double Eagle, unknown date (prior to 1872):

Where the weight of the Half-Eagle should be 8.359 g., a Gold-plated Platinum Counterfeit 

"1869-S" Counterfeit Half-Eagle, San Francisco, CA; 1944.71.1
Weight: 8.441 g. (8.445 g.)
Diameter:  21.5 mm

Counterfeit Double Eagles, $20.