Minerals & Their Properties These notes go on pages 5 and 7 of your INB!

http://www.mii.org/www.mii.org

General Facts about Minerals Between 2 - 3,000 have been identified A few are “native elements” -- made of only one element, such as sulfur, gold. copper, and graphite (carbon) Most are compounds, especially the silicate group (Si, O). Other important groups are oxides, carbonates, and sulfides

The 5 characteristics Inorganic Solid Occurs Naturally Remember the acronym ISODA! Inorganic Solid Occurs Naturally Defined chemical composition Arranged in a crystal

Mineral Groups grouped by the elements they are made of most abundant group are silicates, which are most of the rock-forming minerals Silver Ruby Copper

Elements & Characteristics Mineral Group Elements & Characteristics Examples Silicates contain O and Si most abundant group Quartz Mica Feldspars MICA QUARTZ

make up karst topography, which includes caves Calcite (SiO3) Mineral Group Characteristics Examples Carbonates C and O make up karst topography, which includes caves Calcite (SiO3) Calcite with Duftite inclusions

Mineral Group Characteristics Examples Oxides metallic ion and O Hematite (Fe2)O3

Mineral Group Characteristics Examples Sulfides S and a metallic ion Galena (PbS)

Mineral Group Characteristics Examples Native Elements single elements from the periodic table Gold (Au), Diamond (C), Silver (Ag)

Most Common Minerals: Quartz Feldspar (group) Muscovite (white mica) Biotite (black mica) Calcite Pyroxene Olivine Amphibole (group) Magnetite, limonite, and other iron oxides Pyrite

Minerals are identified by their properties: hardness crystal shape (form) luster color streak cleavage/fracture density or specific gravity special properties --reaction to acid --fluorescence --salty taste --magnetism

Color least useful property for identification: some minerals have more than one color more than one type of mineral can have the same color

Luster describes how light reflects off the surface Main categories are metallic and non- metallic Non-metallic includes: dull, glassy, waxy, pearly, earthy

Hardness ability to scratch another mineral Mohs hardness scale from 1 (talc) to 10 (diamond) Quartz (most common mineral and most dust particles) is a 7

We use a scratch plate to determine hardness.

Streak color of the powder when rubbed on a streak plate (unglazed porcelain) “true color” may be same as hand-specimen or different mineral must be softer than the streak plate

cleavage/fracture Some minerals split along flat surfaces when struck hard-- cleavage Other minerals break unevenly along rough or curved surfaces-- fracture few minerals have both cleavage and fracture

Cleavage or Fracture? 4. 1. 3. 2.

Density & Specific Gravity All minerals have density (mass / volume), but some are very dense Specific Gravity is the density of the mineral compared with density of water (1 g/ml)

Special Characteristics Acid Test: some minerals react to a dilute acid by fizzing (e.g. Carbonate mineral group) Smell: some have a very distint smell (e.g. Sulfur) Taste: certain taste (e.g. Halite, which tastes salty) Attraction to magnets (e.g. magnetite & other iron minerals) Fluorescence is when minerals glow under UV light