You probably noticed I listed two different types of substances, Elements and Compounds . Water can be broken down into Hydrogen and Oxygen. Salt can be broken down into Sodium and Chlorine. Gold, Silver, and Oxygen cannot be separated into anything simpler in an ordinary chemical laboratory. Do notice again that all substances, whether they are elements or compounds, have consistent properties everywhere we find them.
Gold is the same in Arizona as it is in Texas.
Pure water, measured under the same conditions, will have the same properties in New York as it does in Mexico City, etc. When you look carefully at the above definition, you will probably notice this list is pretty short. Think of some obvious mixtures that we are all familiar with like muddy water. The separation becomes apparent as the large particles settle to the bottom and a clear layer forms at the top. This is a good example of our first type of mixture called a Coarse Suspension .