It is the most common gold weight. Heterogeneity means different things to different people. For example, some people say sugar is heterogeneous because each molecule is made up of several types of atoms/molecules. With many elements being used to make up gold, it can be considered heterogeneous. People sometimes use the word "heterogeneous" when they mean "different". A heterogeneous mixture will not all be the same size or shape while a homogeneous one will. A book with pages made of different kinds of paper is an example of a heterogeneous collection of materials. Gold is a heterogeneous mixture because it consists of various types of atoms. The more of these types of atoms there are in gold, the higher its quality and price will be. People also use the word heterogeneity when they mean "not uniform". If a substance is not uniform, then it has different parts. If a particle analysis test shows that a sample of gold is not uniform, this means that there are different types of atoms inside the gold. Heterogeneity is important because it indicates that the gold has some degree of purity.