Minerals and Their Properties

Classifying Minerals A mineral is a naturally formed, inorganic (nonliving) solid that has a definite crystalline structure Element – a substance that cannot be separated or broken down into simpler substances by chemical means Crystal – a solid whose atoms, ions, or molecules are arranged in a definite pattern Compound – a substance made of atoms of two or more different elements joined by chemical bonds

Crystals

Minerals There are four features of minerals: Must occur naturally Must be inorganic (nonliving material) Must be a solid Must have crystalline structure Most minerals are made of compounds of several different elements. A mineral made of only one element is called a native element. (Ex: gold, silver, copper, iron, diamond)

Classifying Minerals Minerals are divided into two groups based on their chemical composition. Silicate Minerals Contain silicon and oxygen Make up 90% of Earth’s crust Nonsilicate Minerals Do NOT contain silicon and oxygen

Identifying Minerals Minerals can be identified by their physical properties. Color - due to impurities and other factors, color is not the best way to identify a mineral Luster - the way the surface of the mineral reflects light

Crystalline Structure - the regular pattern of the atoms in a mineral The way the crystals form and are arranged causes some minerals to break more easily in one direction or another. Fracture –the manner in which a mineral breaks along either curved or irregular surfaces Cleavage – the splitting of a mineral along smooth, flat surfaces

Hardness - a measure of the ability of a mineral to resist scratching Fredrich Mohs developed a hardness scale based on ten relatively common minerals

Streak - the color of the powder of a mineral If you rub a mineral across a porcelain tile (or streak plate) it will leave a stripe of color Density The amount of matter in a given space Density is found by dividing mass by volume (D=m/v) Measured in grams per cubic centimeter (g/cm3)