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 Remember the

acronym ISODA!

1)Inorganic2)Solid3)Occurs Naturally4)Defined chemical

composition5)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 mineralsSilver Ruby

Copper

Mineral Group

Elements & Characteristics

Examples

Silicates

contain O and Si most abundant group

QuartzMica

Feldspars

MICA QUARTZ

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:

1. some minerals have more than one color

2. 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?

1.

4.

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

1. Acid Test: some minerals react to a dilute acid by fizzing (e.g. Carbonate mineral group)

2. Smell: some have a very distint smell (e.g. Sulfur)

3. Taste: certain taste (e.g. Halite, which tastes salty)

4. Attraction to magnets (e.g. magnetite & other iron minerals)

5. Fluorescence is when minerals glow under UV light