Chapter 9 – Minerals and Rocks Lesson 1 – Properties of Minerals

What is a Mineral? Defining Minerals Naturally Occurring Solid Crystal Structure Can be Formed by Inorganic Processes Definite Chemical Composition

Minerals, Compounds, and Elements Almost all minerals are compounds (two or more elements chemically joined) Cinnabar (red) is sulfur (bright yellow) and mercury (silvery liquid) Different minerals have different combinations of elements Some elements, such as copper (Cu), silver (Ag), and gold (Au) occur in nature in pure form. These elements are also minerals.

How Are Minerals Identified? Color Streak Luster Hardness Moh’s Hardness Scale (1  10 – Soft Hard) Talc  Gypsum  Calcite Fluorite  Apatite  Feldspar  Quartz  Topaz  Corundum  Diamond Density Amount of matter in a certain amount space

Crystal Structure Cleavage and Fracture Special Properties Atoms that make up a mineral line up in a regular, repeating pattern Classified according to the number of faces, or sides, on the crystal - Halite – cubic crystals Cleavage and Fracture How the mineral breaks apart Special Properties Some minerals bend light, conduct electricity, glow under UV light, or are magnetic.

How Do Minerals Form? Organic Minerals Minerals from Solutions Calcite CAN come from shells and skeletons of ocean animals such as clams and corals Minerals from Solutions Formed by Evaporation Halite – formed from evaporation of ancient seas (American Southwest and along the Gulf Coast) Gypsum and Calcite Hot Water Solutions Quartz, Silver, and Gold Often form in veins (narrow channel or slab of mineral that is different from the surrounding rock) Minerals from Magma and Lava Magma – Slow cooling – Large crystals – Quartz, Feldspar, Tourmaline, and Mica Lava – Cools quickly – Small crystals – Leucite and olivine

Where Mineral Resources Are Found? Crust is made of the common rock-forming minerals combined in various types of rock Less common minerals are not found evenly distributed throughout the crust Several processes can concentrate these minerals in deposits Ore is a deposit of valuable minerals contained in rocks Iron bearing minerals include pyrite, magnetite, and hematite Lead ores may contain galena Graphite and sulfur are also mined