Pennyweight is derived from the price for a hundred nails in 15th century England: the larger the nail, the higher the cost per hundred. The pennyweight also bears no relation to the weight of the American "penny" (1 cent) coin, which weighs 2.5 g (for those minted after 1982). Pennyweight A pennyweight (abbreviated dwt, from denarius weight) is a unit of mass that is equal to 24 grains, of a troy ounce, of a troy pound, approximately 0.054857 avoirdupois ounce and exactly 1.55517384 grams. In the Middle Ages, a British penny's weight was literally, as well as monetarily, of an ounce
Presolar grains bearing the signature of stellar nucleosynthesis provide information on (i) condensation processes in red giant atmospheres, (ii) radiation and heating processes in the interstellar medium, and (iii) the types of particles that carried the elements of which we are made, across the galaxy to our Solar System. Presolar grains Presolar grains are interstellar solid matter in the form of tiny solid grains that originated at a time before the Sun was formed (presolar: before the Sun). Meteoriticists often use the term to represent "stardust", grains that originated within a single star and which they extract from meteorites for study. Because