Convert from ounce [troy] to uncia [Rome]

Unit Definition (ounce [troy])
The ounce [troy] is a second traditional unit of mass or weight. The troy ounce, traditionally used in pharmacy and jewelry, is 1/12 troy pound, 480 grains, or about 31.1035 grams. Thus the troy ounce equals 192/175 = 1.09714 avoirdupois ounces. This unit is the traditional measure for gold and other precious metals; in particular, the prices of gold and silver quoted in financial markets are the prices per troy ounce. The troy ounce is divided into 20 pennyweight or into 8 troy drams.

Unit Definition (uncia [Rome])
The uncia is the Roman ounce, equal to about 27.2875 grams of 0.9625 ounce avoirdupois. There were 12 ounces in a Roman pound, and the word uncia means a 12th part; its name gives us the ounce, of course, and also the inch.