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IDENTIFYING

MINERALS

COLOR

The way a mineral interacts

with light

Some minerals always have

the same color

Some minerals have a range

of colors

STREAK

The color of the powder

produced by the mineral

Determined by scraping

mineral across a ceramic

plate

Luster

The way a mineral scatters

light

Distinguish between

metallic and non metallic

Hardness

Measure of a mineral’s

ability to resist scratching

Represents the strength of

the bonds

Hard minerals can scratch

soft minerals, but soft

minerals cannot scratch

hard ones

Mohs Hardness Scale : 1 -10

1 =

10 = Diamond –

hardest

Talc -

softest

Crystal Habit

Preferred crystal shape that

forms when a mineral grows

unimpeded

Breakage

How a mineral breaks

depending on the

arrangement of atoms

2 types:

Cleavage

Fracture

Cleavage: mineral breaks along

weak bonds and forms distinct

flat, smooth (planar) surfaces

Fracture: when bonding is

equally strong in all directions,

mineral breaks in an irregular

or curved way

Specific Gravity

The density of a mineral as

compared to the density of

water

Estimate by lifting specimen

Density of pure water

1 g/cm³

Magnetism

Attracts or is attracted to a

magnet

Feel

Certain minerals feel

slippery or greasy

Weak bonds allow atoms to

slide past each other

Taste

A chemical property,

determined by the presence

of certain elements

NEVER TASTE UNLESS

INSTRUCTED TO DO SO!

Odor

A few minerals have a

distinctive odor

Reaction with HCl

Minerals containing a

carbonate anion fizz when

dilute hydrochloric acid is

dropped on them