Troy ounce in the context of Density

The United States dollar (symbol: $; currency code: USD) is the official currency of the United States and several other countries. The Coinage Act of 1792 introduced the U.S. dollar at par with the Spanish silver dollar, divided it into 100 cents, and authorized the minting of coins denominated in dollars and cents. U.S. banknotes are issued in the form of Federal Reserve Notes, popularly called greenbacks due to their predominantly green color.

The U.S. dollar was originally defined under a bimetallic standard of 371.25 grains (24.057 g) (0.7734375 troy ounces) fine silver or, from 1834, 23.22 grains (1.505 g) fine gold, or $20.67 per troy ounce. The Gold Standard Act of 1900 linked the dollar solely to gold. From 1934, its equivalence to gold was revised to $35 per troy ounce. In 1971 all links to gold were repealed. The U.S. dollar became an important international reserve currency after the First World War, and displaced the pound sterling as the world's primary reserve currency by the Bretton Woods Agreement towards the end of the Second World War. The dollar is the most widely used currency in international transactions, and a free-floating currency. It is also the official currency in several countries and the de facto currency in many others, with Federal Reserve Notes (and, in a few cases, U.S. coins) used in circulation.

The Florentine florin was a gold coin (in Italian Fiorino d'oro) struck from 1252 to 1533 with no significant change in its design or metal content standard during that time.

It had 54 grains (3.499 grams, 0.1125 troy ounces) of nominally pure or 'fine' gold with a purchasing power difficult to estimate (and variable) but ranging according to social grouping and perspective from approximately 140 to 1,000 modern US dollars. The name of the coin comes from the Giglio bottonato (it), the floral emblem of the city, which is represented at the head of the coin.

The Bretton Woods system of monetary management established the rules for commercial relations among 44 countries, including the United States, Canada, Western European countries, and Australia, after the 1944 Bretton Woods Agreement until the Jamaica Accords in 1976. The Bretton Woods system was the first example of a fully negotiated monetary order intended to govern monetary relations among independent states. The Bretton Woods system required countries to guarantee convertibility of their currencies into U.S. dollars to within 1% of fixed parity rates, with the dollar convertible to gold bullion for foreign governments and central banks at US$35 per troy ounce of fine gold (or 0.88867 gram fine gold per dollar). It also envisioned greater cooperation among countries in order to prevent future competitive devaluations, and thus established the International Monetary Fund (IMF) to monitor exchange rates and lend reserve currencies to countries with balance of payments deficits.

Preparing to rebuild the international economic system while World War II was still being fought, 730 delegates from all 44 Allied countries gathered at the Mount Washington Hotel in Bretton Woods, New Hampshire, United States, for the United Nations Monetary and Financial Conference, also known as the Bretton Woods Conference. The delegates deliberated from 1 to 22 July 1944, and signed the Bretton Woods agreement on its final day. Setting up a system of rules, institutions, and procedures to regulate the international monetary system, these accords established the IMF and the International Bank for Reconstruction and Development (IBRD), which today is part of the World Bank Group. The United States, which controlled two-thirds of the world's gold, insisted that the Bretton Woods system rest on both gold and the US dollar. Soviet representatives attended the conference but later declined to ratify the final agreements, charging that the institutions they had created were "branches of Wall Street". These organizations became operational in 1945 after a sufficient number of countries had ratified the agreement. According to Barry Eichengreen, the Bretton Woods system operated successfully due to three factors: "low international capital mobility, tight financial regulation, and the dominant economic and financial position of the United States and the dollar."

The English penny (plural "pence"), originally a coin of 1.3 to 1.5 grams (0.042 to 0.048 troy ounces; 0.046 to 0.053 ounces) pure silver, was introduced c. 785 by King Offa of Mercia. These coins were similar in size and weight to the continental deniers of the period and to the Anglo-Saxon sceats which had preceded it.

Throughout the period of the Kingdom of England, from its beginnings in the 9th century, the penny was produced in silver. Pennies of the same nominal value, 1⁄240 of a pound sterling, were in circulation continuously until the creation of the Kingdom of Great Britain in 1707.

A pennyweight (dwt) is a unit of mass equal to 24 grains, 1⁄20 of a troy ounce, 1⁄240 of a troy pound, 48⁄875 avoirdupois ounce and exactly 1.55517384 grams. It is abbreviated dwt, d standing for denarius – (an ancient Roman coin), and later used as the symbol of an old British penny (see £sd).

The tola (Hindi: तोला / Urdu: تولا, romanized: tolā; also transliterated as tolah or tole) is a traditional South Asian unit of mass, now standardised as 180 grains (11.6638038 grams) or exactly 3⁄8 troy ounce. It was the base unit of mass in the British Indian system of weights and measures introduced in 1833, although it had been in use for much longer. It was also used in Aden and Zanzibar: in the latter, one tola was equivalent to 175.90 troy grains (0.97722222 British tolas, or 11.33980925 grams).

The tola is a Vedic measure, with the name derived from the Sanskrit तोलः tolaḥ (from the root तुल् tul) meaning "weighing" or "weight". One tola was traditionally the weight of 100 Ratti (ruttee) seeds, and its exact weight varied according to locality. However, it is also a convenient mass for a coin: several pre-colonial coins, including the currency of Akbar the Great (1556–1605), had a mass of "one tola" within slight variation. The first rupee (Urdu: رپيا; rupayā), minted by Sher Shah Suri (1540–45), had a mass of 178 troy grains, or about 1% less than the British tola. The British East India Company issued a silver rupee coin of 180 troy grains, and this became the practical standard mass for the tola well into the 20th century.

A zolotnik (Russian: золотни́к, abbr.: zol.) is an obsolete Russian unit of weight, equal to 0.1505 avoirdupois ounces, 0.13715 troy ounce, or 4.2658 grams (about 65.83 grains). Used from the 10th to 20th centuries, its name is derived from the Russian word zoloto, meaning gold. As a unit, the zolotnik was the standard for silver manufacture, much as the troy ounce is currently used for gold and other precious metals.

This unit was originally based on a coin of the same name. The zolotnik circulated in the Kievan Rus until the 11th century; it was equal in weight to the Byzantine Empire's solidus.

A sceat or sceatta (/ʃæt/ SHAT; Old English: sceatt [ʃæɑt], pl. sceattas) was a small, thick silver coin minted in England, Frisia, and Jutland during the Anglo-Saxon period that normally weighed 0.8–1.3 grams (about 1⁄30 troy ounce). It is now (as of 2024) more commonly known in England as an 'early penny'.

The Britannia is a bullion coin issued by the Royal Mint. It has been minted in gold since 1987, in silver since 1997, and in platinum since 2018. The reverse of the coin patterns feature various depictions of Britannia, a feminine personification of the United Kingdom, while the obverse features the effigy of the monarch of the United Kingdom with the legend around it.

Britannia gold coins contain one troy ounce of gold and have a face value of £100. Gold Britannias also are issued in fractional sizes of one-half, one-quarter, and one-tenth of a troy ounce and with face values of £50, £25, and £10 respectively. In 2013, two additional sizes were introduced, a five-ounce coin of face value £500, and a fractional size of one-twentieth of face value £5.

The Canadian Gold Maple Leaf (GML; French: Feuille d'érable en or canadienne) is a gold bullion coin that is issued annually by the Government of Canada. It is produced by the Royal Canadian Mint.

The Gold Maple Leaf is legal tender with a face value of 50 Canadian dollars. The market value of the metal varies, depending on the spot price of gold. Having a .9999 millesimal fineness (24 karats), in some cases .99999, the coin is among the purest official bullion coins worldwide. The standard version has a weight of minimum 1 troy ounce (31.1 grams). Other sizes and denominations include: 1 gram, 1⁄25 oz. ($0.50), 1⁄20 oz. ($1), 1⁄10 oz. ($5), 1⁄4 oz. ($10) and 1⁄2 oz. ($20).