Download Minerals Property Descriptions and Testing Procedures:

Other properties: Here are three additional
Minerals Property Descriptions and
Testing Procedures:
tests that you should perform on all your rocks.
Cleavage or fracture: These two properties refer to
If you get a positive test, record it in your OTHER
Color: This is probably the most easily observed
the way in which a mineral breaks. Cleavage is an
PROPERTIES COLUMN.
property of minerals. However, color often varies
orderly breakage in well-defined planes, meaning the

widely and is the least reliable property for
mineral has flat sides. Fracture is a random breakage.
particular taste. Two minerals halide and
identification.
If a mineral breaks with rough, random surfaces, it is
quartz are very similar in appearance. One
Streak: The color of the mineral when powdered. To
said to have fracture.
simple way to tell them apart is that halide
test for streak, draw the mineral against an unglazed
Density of a mineral is the mass in a given space, or
has a salty taste whereas, quartz has no
porcelain tile (streak plate). Streak is more useful for
mass per unit volume. No matter what the size of a
identification than color is.
mineral sample, the density of that mineral remains
Hardness: A mineral’s hardness is it’s resistance to
the same. Density=mass ÷ volume
scratching. A mineral can scratch any mineral softer
Heft: Compare the relative “heft” of a mineral by
than itself, but can be scratched by any mineral
holding it in your hand, feeling the weight and
harder than itself. Mohs Scale of Hardness, this scale
comparing it to other minerals of about the same size.
uses common everyday objects to test hardness of
In general, metallic minerals are heavier than non-
each mineral sample. Below is the resulting table.
metallic minerals. For ease minerals are classified as
taste.

Rating
Object used to test Hardness
smells like rotten eggs..

1
(shiny and gold or silver color) and nonmetallic luster
2
Fingernail-2.5
(does not look like a metal in color, although it may be
3
Penny-3.5
shiny). Particular types of nonmetallic luster include
4
Nail-4.5
pearly, vitreous (glassy), resinous (has the
5
Glass-5.5
appearance of resin), silky, and earthy (dull).
6
Steel file-6.5
7
Streak plate-7
Crystal Systems: Repeating groups of crystals that
8
9
10
make up a mineral’s structure. Grouped based on the
number and angle of crystal faces.
NOTES:________________________________________
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ACID TEST: You should test all your rocks
to see if they will react with hydrochloric
acid. Place all your rocks on a paper towel
and put a single drop on each rock, one at
a time. If you immediately see a vigorous
fizzing in the drop, it is calcite. Dry them a
Luster: Refers to the way that a mineral reflects light.
The simplest distinction is between metallic luster
SMELL TEST: Certain minerals give off a
very distinct smell. Sulfur for instance
1.) light, 2.) heavy, 3.) very heavy.
Moh’s scale of Hardness
TASTE TEST: Certain Minerals have a
paper towel after you are done.

MAGNET TEST: if one of your rocks is
attracted to a magnet, it may be magnetite.
But check all the other properties too
because other iron ores are also easily
magnetized.

FLORESCENCE: Scheelite glows in
ultraviolet light.

REACTIVITY: Aragonite reacts chemically
to acids.

OPTICAL PROPERTIES: Calcite bends
light to produce a double image.