Notes=red Minerals

What is a mineral? A mineral is a naturally formed, inorganic solid with a crystalline structure. Not all minerals look like gems… in fact, most look like rocks! Rocks are made of minerals but minerals are not made of rocks.

Mineral vs Rock In order to be a mineral, it must have these four properties: It has to be a solid It has to be formed in nature It has to be inorganic It has to have a crystalline structure But what do those mean?

Solid The three phases of matter are solid, liquid, and gas. A solid has a defined shape: it does not change. Minerals cannot be liquids or gases but can be found in and around liquids and gases.

Formed in nature In order to be a mineral, it has to be created in nature. There are many things that are “man-made” items. These items, which can even sometimes look like minerals, are not minerals because they do not form in nature! It has to be naturally occurring! Something you could dig up or find lying around.

Inorganic Inorganic means “not organic” or “not living” Minerals must be things that are not alive.

Crystalline structure When you think of crystals you usually think of a rigid structure. The exact shape depends on the arrangement of atoms. Almost all minerals are made of the one chemical composition throughout.

Chemical composition? composition= what something is made of Minerals are made of elements. All minerals have one or more of the 92 elements that are present on the Earth’s crust.

More on elements An element is made of only one kind of atom. An atom is the basic unit of an element. Some minerals have more than one element. These minerals are made of compounds of elements. (think compound words) A compound has 2 or more elements that are bonded together.

Properties of minerals How can you tell two minerals apart? Scientists have organized mineral properties into categories to help identify unknown minerals. The seven major properties of minerals are: Color, luster, streak, cleavage, fracture, hardness, and density.

Color What color you see

Luster How the mineral reflects light. Think “shiny” and “dull”

Streak The color of the mineral when in powder form. Color does not equal streak!!! In order to find streak, the mineral needs to be rubbed against a porcelain streak plate.

Cleavage How often a mineral breaks along a flat surface.

Fracture How often a mineral breaks unevenly, curved, or rigidly. (Think fractured bones!)

Hardness How resistant the mineral is to being scratched. Uses Moh’s hardness scale

Moh’s Scale