Cameron Dudzinski
Professor Jason Lee
GEL111
16 January 2021
Unit 1 Assignment
When identifying rocks/minerals, there are many steps and parts to determine their
identity. For identifying rocks, you have to find what minerals compose to make the rock, and for
minerals its physical properties are taken into account to determine which they are, ultimately
being used for rock identification as well.
From picking the mineral to test, the easiest way to start it by going through color, streak,
and luster when first starting. Mineral color is very useful for the identification process but can
be misleading from just color alone. The reason for this is that many minerals may share the
same colors, or even have multiple colors, such as quartz which comes in a large variety of color
differences. Color is very helpful but isn’t to be too relied on, it’s mainly just a stepping stone for
the start of the process. However, luster, which describes the reflection of light off the mineral, is
much more helpful when it comes to mineral identification. What makes this different from color
is that luster can be referred to as “shiny” or “dull”, while color is as simple as just being stated
as “yellow”. Other examples of luster descriptions include; glassy, pearly, silky, greasy, and
more, this typically being used to see if a mineral has a metallic luster. And then after color and
luster, the streak is the next best way to test a mineral.s identification. Streak refers to the color
of a mineral’s powder, also being more reliable than color, because streak does not vary among
This study source was downloaded by 100000838319108 from CourseHero.com on 12-14-2021 10:28:23 GMT -06:00
https://www.coursehero.com/file/86369102/Dudzinski-Unit-1-Assignment-11621/
, minerals. To check streak, you have to scrape the mineral against a plate, and will leave behind a
trail of color that will be a strong indicator of what its identity is.
After that, density, hardness, cleavage, fracture, and crystal shape are the next things to
test in the mineral identification process. Density describes the amount of matter of space that the
mineral takes up when it comes to its volume, the specific gravity of a substance compared to the
density of water for instanced would measure the difference in higher or lower specific gravity
and density. Hardness is the strength that the mineral has in resistance against another surface as
it’s tested in physical force and tests. Most people doing the test for mineral identification would
use the Mohs hardness scale for this test, having the scale based on ten different mineral
examples, having it be able to put the mineral in question somewhere on the scale for
comparison and contrast. Cleavage is the habit for a mineral to break in certain ways to make a
surface smooth, such as halite which breaks on layers of sodium and chlorine and forms smooth
cubes. Essentially, a mineral that breaks naturally into a smooth surface shows that it has
cleavage, showing a form of weakness in the mineral. Fracture is when a mineral has a break in it
that isn’t on the same plane as cleavage would be, fracture isn’t going to be the same for each
mineral because it’s a structural difference. The fracture can be determined by smashing it for
instance, but should only be used when truly no cleavage is identified, such as quartz that has no
cleavage, and when broke, fractures into all directions. And finally, crystal shape is determined
by the chance that the mineral exhibits the shape of their crystal forms, not necessarily because
they are crystalline though. Most minerals do not exhibit any crystal form, but to determine this a
mineral must be given space to grow for it to be able to form its natural crystal structure.
There are other forms of identification, such as; fluorescence, magnetism, radioactivity,
reactivity, smell, and taste, but the ones I have mentioned are the more important ones when it
This study source was downloaded by 100000838319108 from CourseHero.com on 12-14-2021 10:28:23 GMT -06:00
https://www.coursehero.com/file/86369102/Dudzinski-Unit-1-Assignment-11621/
Professor Jason Lee
GEL111
16 January 2021
Unit 1 Assignment
When identifying rocks/minerals, there are many steps and parts to determine their
identity. For identifying rocks, you have to find what minerals compose to make the rock, and for
minerals its physical properties are taken into account to determine which they are, ultimately
being used for rock identification as well.
From picking the mineral to test, the easiest way to start it by going through color, streak,
and luster when first starting. Mineral color is very useful for the identification process but can
be misleading from just color alone. The reason for this is that many minerals may share the
same colors, or even have multiple colors, such as quartz which comes in a large variety of color
differences. Color is very helpful but isn’t to be too relied on, it’s mainly just a stepping stone for
the start of the process. However, luster, which describes the reflection of light off the mineral, is
much more helpful when it comes to mineral identification. What makes this different from color
is that luster can be referred to as “shiny” or “dull”, while color is as simple as just being stated
as “yellow”. Other examples of luster descriptions include; glassy, pearly, silky, greasy, and
more, this typically being used to see if a mineral has a metallic luster. And then after color and
luster, the streak is the next best way to test a mineral.s identification. Streak refers to the color
of a mineral’s powder, also being more reliable than color, because streak does not vary among
This study source was downloaded by 100000838319108 from CourseHero.com on 12-14-2021 10:28:23 GMT -06:00
https://www.coursehero.com/file/86369102/Dudzinski-Unit-1-Assignment-11621/
, minerals. To check streak, you have to scrape the mineral against a plate, and will leave behind a
trail of color that will be a strong indicator of what its identity is.
After that, density, hardness, cleavage, fracture, and crystal shape are the next things to
test in the mineral identification process. Density describes the amount of matter of space that the
mineral takes up when it comes to its volume, the specific gravity of a substance compared to the
density of water for instanced would measure the difference in higher or lower specific gravity
and density. Hardness is the strength that the mineral has in resistance against another surface as
it’s tested in physical force and tests. Most people doing the test for mineral identification would
use the Mohs hardness scale for this test, having the scale based on ten different mineral
examples, having it be able to put the mineral in question somewhere on the scale for
comparison and contrast. Cleavage is the habit for a mineral to break in certain ways to make a
surface smooth, such as halite which breaks on layers of sodium and chlorine and forms smooth
cubes. Essentially, a mineral that breaks naturally into a smooth surface shows that it has
cleavage, showing a form of weakness in the mineral. Fracture is when a mineral has a break in it
that isn’t on the same plane as cleavage would be, fracture isn’t going to be the same for each
mineral because it’s a structural difference. The fracture can be determined by smashing it for
instance, but should only be used when truly no cleavage is identified, such as quartz that has no
cleavage, and when broke, fractures into all directions. And finally, crystal shape is determined
by the chance that the mineral exhibits the shape of their crystal forms, not necessarily because
they are crystalline though. Most minerals do not exhibit any crystal form, but to determine this a
mineral must be given space to grow for it to be able to form its natural crystal structure.
There are other forms of identification, such as; fluorescence, magnetism, radioactivity,
reactivity, smell, and taste, but the ones I have mentioned are the more important ones when it
This study source was downloaded by 100000838319108 from CourseHero.com on 12-14-2021 10:28:23 GMT -06:00
https://www.coursehero.com/file/86369102/Dudzinski-Unit-1-Assignment-11621/
