Minerals & Their Properties
description
Transcript of Minerals & Their Properties
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