Gold: the intrinsic (fine-gold) value of 24, 22, 18 and 14 karat gram gold, the troy ounce and, by the Turkish Mint's weights, the çeyrek, yarım, tam, ikibuçuk, beşli, Cumhuriyet and Ata beşli coins, every business day since 2 January 2013. The source is the price of 1 g of fine gold calculated by Narodowy Bank Polski (NBP); USD and EUR use NBP's rates of the same day, TRY goes through USD at TCMB's forex midpoint. These are melt values without workmanship or a dealer's spread; a Grand Bazaar dealer's price is higher.
Commodities: daily spot prices of Brent, WTI, Henry Hub natural gas, gasoline, diesel, heating oil, jet fuel and propane from the US Energy Information Administration (EIA; released weekly, since 1986) and monthly average prices of 67 commodities from the World Bank, including metals, energy, grains, oils, fertilizers and timber (since 1960). Prices are in US dollars. Sources: NBP; TCMB; EIA; World Bank Commodity Price Data (The Pink Sheet), CC BY 4.0.