©Dr. Mitchel Goodkin, 2009. Identify an unknown rock sample by testing it through the basic properties of minerals. S1a- Demonstrates understanding of

©Dr. Mitchel Goodkin, 2009

Identify an unknown rock sample by testing it through the basic properties of minerals.

S1a- Demonstrates understanding of properties of objects and materials.

S3a- Demonstrates understanding of properties of Earth materials

S6a- Uses technology and tools to gather data and extend the senses ©Dr. Mitchel Goodkin, 2009

We now can use a reference chart.


Diamond Quartz Calcite Florite UNKNOWN

Color Clear Clear Clear Clear

Luster Yes Yes Yes Yes

Cleavage Fracture

CleavageConchoidial

FractureCleavage Cleavage

Streak None White White White

Crystals Yes Yes Yes Yes

Magnetic No No No No

Density3.5–3.53 g/cm3

2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo

ReactionNo Reaction Reacts

No Reaction

How do we tell one mineral from another ?

Using the mineral properties and tests that we’ve already learned, we can

determine the identity of an unknown sample.


http://www.mineralminers.com/images/calcite/mins/calm136.jpg

The first property on the chart is color.

Look at our unknown and determine what color it is.



Fill your answer on the chart.





Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

Clear

Which of the samples listed on the table is clear ?

Which is NOT clear ?Can we eliminate any possibilities based

on color ?

The second property on the chart is luster.

Look at our unknown, maybe use a flashlight, and determine if it has luster.








Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

Clear

Yes

Which of the samples listed on the table has luster ?

Which does NOT have luster ?Can we eliminate any possibilities based

on luster ?

The next property on the chart is cleavage or fracture.

Our unknown shows evidence of cleavage.






Color Clear Clear Clear Clear Clear

Luster Yes Yes Yes Yes Yes

Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

Cleavage

Which of the samples listed on the table has cleavage ?

Which does NOT have cleavage ?Can we eliminate any possibilities based

on cleavage ?






Cleavage Fracture

CleavageConchoidial

FractureCleavage Cleavage Cleavage





2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

We can eliminate Quartz as a possibility for our unknown sample.

Quartz does conchoidial type fractures while our unknown does cleavage.

We don’t have to look at the Quartz column ever again for this sample.

The next property on the chart is streak.

When we scratch our unknown on a porcelain tile it leaves a white mark.








Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

Which of the samples listed on the table left a white streak ?

(Remember, don’t look at Quartz, it’s eliminated)

Which does NOT have a white streak ?Can we eliminate any possibilities based

on streak ?

White






Cleavage Fracture

CleavageConchoidial


Streak None White White White White




2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

We can eliminate Diamond as a possibility for our unknown sample.

Diamonds leave no streak on our tile.We don’t have to look at the Diamond

column ever again for this sample.

The next property on the chart is crystals.

Look at our unknown and determine if it has a crystal type shape.








Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

Which of the samples listed on the table has crystals ?

(Remember, don’t look at Quartz or Diamond, they’re eliminated)

Which does NOT have a crystals ?Can we eliminate any possibilities based

on crystals ?

Yes

The next property on the chart is magnetism.

Can our sample pick up items like a magnet, or can it be picked up by a

magnet ?








Cleavage Fracture

CleavageConchoidial



Crystals Yes Yes Yes Yes Yes



2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

No

Which of the samples listed on the table are magnetic ?


Which are NOT magnetic ?Can we eliminate any possibilities based

on magnetism ?

The next property on the chart is density.

We can calculate the density of our unknown and enter it onto the chart.



Fill in your answer on the chart.





Cleavage Fracture

CleavageConchoidial




Magnetic No No No No No


2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

About 2.7g/cm3

Is the calculated density of our sample the same as or close to a density on the chart?


Can we eliminate any possibilities based on density ?






Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

About 2.7 g/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

We can eliminate Florite as a possibility for our unknown sample.

The density of Florite is 3.18 g/cm3 and the density of our sample is 2.7 g/cm3.






Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

About 2.7 g/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

Now that we have eliminated every other possibility on our chart, we can say that

our unknown is CALCITE !!In order to reinforce this statement, we should fill in the rest of the chart for the

remaining properties of our sample.

The next property on the chart is hardness.

We perform a scratch test on our sample.It IS scratched by Diamond (10), Quartz (7) and Florite (4), so

we know it’s softer than those. It is not scratched by Calcite(3), and it doesn’t leave a scratch mark on Calcite

either so it must be the same as Calcite (3).








Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

About 2.7 g/cm3

Hardness 10 7 3 4

Acid TestNo


No Reaction

3

We are approximating by comparison that the hardness of our sample is 3.

Is this what we’d expect for Calcite ? If not we might have to run more tests.

The last property on the chart is the acid test.

We put a drop of acid on our sample and it bubbles which means a reaction is

occurring.








Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

About 2.7 g/cm3

Hardness 10 7 3 4 3

Acid TestNo


No Reaction

Reacts

The sample reacts to acid and bubbles.Is this what we’d expect for Calcite ?

If not we might have to run more tests.

BEFORE we say that this is Calcite, let’s double check the

reference chart and our results one more time.



Double check the reference chart.





Cleavage Fracture

CleavageConchoidial






2.65 - 2.66 g/cm3

2.711 g/cm3

3.18 gm/cm3

About 2.7 g/cm3

Hardness 10 7 3 4 3

Acid TestNo


No Reaction

Reacts

Do ALL of our sample results match the chart

results for Calcite ?

At this point, we can safely say…

Our unknown isCALCITE !!!!!

**SPECIAL NOTES**


Just to keep things simple, “clear” was used for some of the answers on the chart. Really, it depends if something is mixed into the rock, the rock might have other colors completely; such as purples, blues, pinks or yellows.

Also, to keep things simple, the word “luster” was used. When speaking about “luster” the term metallic

or non-metallic is usually used.Non-Metallic Metallic

http://images.google.com/imgres?imgurl=http://www.minresco.com/display/djpg/mi073.jpg&imgrefurl=http://www.minresco.com/display/disp19.htm&usg=__pLr8YWhehJWKehKsmpY0V3caBjY=&h=287&w=408&sz=28&hl=en&start=5&sig2=BJ5ov-9i5Nk-Qnr9ZIknnQ&tbnid=vMb1F-pG8iRQsM:&tbnh=88&tbnw=125&prev=/images%3Fq%3Dcolored%2Bquartz%2Bcrystal%26gbv%3D2%26hl%3Den%26safe%3Dactive%26rls%3Dig&ei=pMvUStiRK5bUlQf5kqmdCQ

http://www.mineralminers.com/images/pyrite/mins/pytm162.jpg

http://www.mineralminers.com/images/chalcedony/mins/chlm144.jpg

http://www.mineralminers.com/images/smoky-quartz/mins/smqm112.jpg

http://www.mineralminers.com/images/hematite/mins/hemm129.jpg

xxxx


Documents

©Dr. Mitchel Goodkin, 2009. Identify an unknown rock sample by testing it through the basic properties of minerals. S1a- Demonstrates understanding of