what does pennyweight mean
A pennyweight (abbreviated dwt) is a unit of mass that is equal to 24 grains, 1â20 of a troy ounce, 1â240 of a troy pound, approximately 0.054857 avoirdupois ounce and exactly 1.55517384 grams.hen Troy weights replaced Tower weights in 1527, the Troy weights were defined in such a way that the old Tower pound came out to exactly 5400 Troy grains (also known as barleycorns), the Tower pennyweight 22 1â2 Troy grains (and thus approximately 1.46 grams).