Convert metric decatonne to troy ounce

Gold, silver and platinum are priced per troy ounce, 31.103 g, which is about 10 % heavier than the ordinary (avoirdupois) ounce of 28.35 g. Twelve troy ounces make a troy pound of 373 g, 20 pennyweights make an ounce, and the grain, 64.8 mg, is the one unit the two systems share; it also survives in the weights of bullets and, in the US, of old-fashioned medicine doses (5 grains of aspirin is 324 mg). A standard 400 oz 'good delivery' gold bar weighs 12.4 kg.