Presumably at market in St. Petersburg, Platinum was valued 4x less than Gold. The exchange with Madrid was 1 peso of 20 reales (23.36 grams of Fine Ag) for 1.32 Roubles.
Madrid was 1 peso duro for Fr 5.29 or £ 0.212 (4.725 pesos per £) =
Citation: Manual del banquero, del agente de bolsa y del corredor de cambios ; Angel Henry (1855) p.71
The Paper-Gold Rouble exchange was considered stable, at par:
The price of bar-iron in the Urals, a product exported: