What is a mineral? A mineral is a naturally formed, inorganic solid that has a definite crystalline structure. Inorganic means that they are not made of living things. Characteristics of minerals 1. Minerals are formed by natural processes. 2. Minerals are inorganic which means that they are not made from living things. 3. Minerals are crystals, which have a repeating inner structure. 4. Minerals have the same chemical composition throughout. What are elements? Elements are pure substances that cannot be broken down into simpler substances by ordinary chemical reactions. What is an atom? An atom is the smallest part of an element that has all the properties of that element. Each element is made up of only one atom. What is a compound? A compound is a substance made up of two or more elements that have been chemically joined, or bonded. Example: Na is sodium Cl is chloride NaCl is a compound of sodium and chloride. A mineral that is composed of only one element is called a native element. What is a crystal? A crystal is a solid whose atoms, ions, or molecules are arranged in a definite pattern. Groups of minerals Minerals are divided into groups based on their chemical composition. These groups are: 1. Silicate minerals 2. Non-silicate minerals Silicate minerals Minerals that contain a combination of Silicon and Oxygen are called Silicate minerals. Silicate minerals make up 90% of the Earth’s crust. Non-silicate minerals Minerals that do not contain a combination of the elements silicon and oxygen form a group called non-silicate minerals.