CrabSO Invitational - MD — Rocks and Minerals

Rocks and Minerals · Division B · CrabSO Invitational - MD · 2026

113 questions · 153 points · 50 min· 2 questions from the original omitted

DO NOT WRITE ON THE TEST Do not take the test apart You will have 5 minutes per station Tiebreakers will be the scores on each station from back to front Ex: TB1 is the score on Station 10, TB2 is the score on Station 9, etc.

Station 1 - Hidden Gems

FigureFor questions 1A, 1B, 1C, 1D, 1E, 1F

Question 1A

1 pt

Identify specimen 1A.

Question 1B

1 pt

Identify specimen 1B.

Question 1C

1 pt

Identify specimen 1C.

Question 1D

1 pt

Identify specimen 1D.

Question 1E

1 pt

Identify specimen 1E.

Question 1F

1 pt

Identify specimen 1F.

Question 3

1 pt

Emerald is a precious green variety of what mineral?

A. CorundumB. DioptaseC. BerylD. Olivine

Question 4

1 pt

Ruby and sapphire are red and blue gemstone varieties of what mineral?

A. TourmalineB. CorundumC. BerylD. Quartz

Question 5

1 pt

What ion gives Specimen 1E its distinctive purple color?

A. Cu⁺B. Cu²⁺C. Fe²⁺D. Fe³⁺

Question 6

1 pt

The gemstone variety of which specimen is the birthstone for August?

A. 1AB. 1BC. 1CD. 1D

Question 7

2 pts · select all that apply

Which of the specimens are defining minerals on the Mohs hardness scale? Select all that apply.

A. 1AB. 1BC. 1CD. 1D

Question 8

4 pts

What mineral has the same chemical formula as Specimen 1D, and how is their bonding structure different? Explain your answers in terms of chemical bonding.

Question 9

2 pts

Specimen 1F is a cryptocrystalline variety of what mineral? Briefly explain what it means to be cryptocrystalline.

Station 2 - Metallica

FigureFor questions 2-1A, 2-1B, 2-1C, 2-1D, 2-1E, 2-1F

Question 2-1A

1 pt

Identify specimen 2A.

Question 2-1B

1 pt

Identify specimen 2B.

Question 2-1C

1 pt

Identify specimen 2C.

Question 2-1D

1 pt

Identify specimen 2D.

Question 2-1E

1 pt

Identify specimen 2E.

Question 2-1F

1 pt

Identify specimen 2F.

Question 2-3

1 pt

What type of chemical bond involves a free-flowing “sea” of electrons that promotes electrical conductivity?

A. IonicB. CovalentC. MetallicD. Hybrid

Question 2-4

2 pts · select all that apply

Which specimens are oxides? Select all that apply.

Question 2-5

1 pt

Specimen 2F is an ore of what element?

A. IronB. CopperC. NickelD. Zinc

Question 2-6

2 pts

Name two properties that make a mineral a good ore.

Question 2-7

1 pt

Ores are often not found in isolation; there are usually other minerals that surround it, but are not considered commercially useful. These minerals are often mined through to get to the ore. What are these minerals called?

A. GangueB. WasteC. StockD. Pile

Question 2-8

1 pt

Which specimen above is an ore of titanium?

Question 2-9

1 pt

What family of minerals tends to have a wiry or dendritic mineral habit?

A. BoratesB. SulfidesC. OxidesD. Native elements

Question 2-10

1 pt

The mineral pyrite is often called “fool’s gold” due to its appearance. What property would NOT help you distinguish gold from pyrite?

A. HardnessB. LusterC. HeftD. Mineral habit

Station 3 - Hard Rock Cafe

FigureFor questions 3-1A, 3-1B, 3-1C, 3-1D, 3-1E, 3-1F, 3-3

Question 3-1A

1 pt

Identify specimen 3A.

Question 3-1B

1 pt

Identify specimen 3B.

Question 3-1C

1 pt

Identify specimen 3C.

Question 3-1D

1 pt

Identify specimen 3D.

Question 3-1E

1 pt

Identify specimen 3E.

Question 3-1F

1 pt

Identify specimen 3F.

Question 3-3

3 pts

Rank Specimens 3A through 3F by increasing hardness. If two minerals have the same hardness, use an equal sign.

Question 3-4

1 pt

What value is closest to the Mohs hardness of a streak plate?

A. 4B. 5C. 7D. 8

Question 3-5

1 pt

Which of the following is NOT a scale of absolute hardness?

A. MohsB. BrinellC. VickersD. Rockwell

Question 3-6

1 pt

Rebecca has an unknown mineral sample. This mineral cannot be scratched by her fingernail, but it can be scratched by a penny. What could its hardness be?

A. 2B. 3C. 4D. 5

Question 3-7

1 pt

Two specimens out of the ones above have a hardness of 5. What group do these specimens belong to?

A. Apatite GroupB. Tourmaline GroupC. Pyroxene GroupD. Amphibole Group

Question 3-8

1 pt

Specimen 3E has a sectile tenacity. What does this mean?

A. It breaks easilyB. It can be drawn into wiresC. It splits into sheetsD. It can easily be cut with a knife

Question 3-9

2 pts

Cleavage and fracture both describe how a mineral breaks, but how are they different?

PassageFor question 3-10

Use the following image to answer Question 10.

Question 3-10

2 pts

Identify the Miller index of the cleavage plane shown above. Assume x is to the right, y is toward you, and z is upward. Write your answer in the format {hkl}.

Station 4 - Steve’s Lava Chicken

FigureFor questions 4-1A, 4-1B, 4-1C, 4-1D, 4-1E, 4-1F

Question 4-1A

1 pt

Identify specimen 4A.

Question 4-1B

1 pt

Identify specimen 4B.

Question 4-1C

1 pt

Identify specimen 4C.

Question 4-1D

1 pt

Identify specimen 4D.

Question 4-1E

1 pt

Identify specimen 4E.

Question 4-1F

1 pt

Identify specimen 4F.

Question 4-3

1 pt

What word best describes the texture of Specimen 4A?

A. PhaneriticB. AphaniticC. PegmatiticD. Porphyritic

Question 4-4

1 pt

What does the texture of Specimen 4D indicate about its cooling time?

A. Specimen 4D cooled very quicklyB. Specimen 4D cooled very slowlyC. Specimen 4D cooled quickly, then slowlyD. Specimen 4D cooled slowly, then quickly

Question 4-5

2 pts · select all that apply

Select all minerals that have a mafic composition.

Question 4-8

2 pts

Another system for classifying igneous rocks is the total-alkali-silica (TAS) system. When is the TAS system used as opposed to the QAPF system?

Question 4-9

1 pt

What happens to the composition of magma over time before it erupts from a volcano?

A. It gets more felsicB. It gets more maficC. It stays the sameD. Depends on the initial conditions of the magma

Station 5 - Fossils Returns (sort of)

FigureFor questions 5-1A, 5-1B, 5-1C, 5-2

Question 5-1A

1 pt

Identify specimen 5A.

Question 5-1B

1 pt

Identify specimen 5B.

Question 5-1C

1 pt

Identify specimen 5C.

Question 5-2

3 pts

Classify the textures of the specimens above as clastic, chemical, or organic. Answers may be repeated or not used at all.

Question 5-3

1 pt

What type of rock is most likely to contain fossils?

A. IgneousB. SedimentaryC. MetamorphicD. All are equally likely

Question 5-4

1 pt

What ancient species of fern primarily makes up modern-day varieties of Specimen 5C?

A. GlossopterisB. LepidodendronC. MetasequoiaD. Ginkgo

Question 5-5

1 pt

What element is responsible for making red shales their distinctive red color?

A. CopperB. IronC. LithiumD. Chromium

Question 5-6

1 pt

Which sedimentary rock is most susceptible to chemical weathering?

A. SandstoneB. ShaleC. LimestoneD. Siltstone

Question 5-7

1 pt

Which of the following is NOT a feature of a karst landscape?

A. SpeleothemB. MoraineC. SinkholeD. Cenote

Question 5-8

1 pt

Which specimen is known to be fissile?

A. 5AB. 5BC. 5CD. None

Question 5-9

1 pt

What mineral habit looks like a branching bryozoan? (HINT: branching is a key word)

Question 5-10

2 pts

Rank the following specimens by increasing energy density: A) Bituminous Coal, B) Anthracite, C) Lignite, D) Peat

Station 6 - Silly cats

FigureFor questions 6-1A, 6-1B, 6-1C, 6-1D, 6-1E, 6-1F

Question 6-1A

1 pt

Identify specimen 6A.

Question 6-1B

1 pt

Identify specimen 6B.

Question 6-1C

1 pt

Identify specimen 6C.

Question 6-1D

1 pt

Identify specimen 6D.

Question 6-1E

1 pt

Identify specimen 6E.

Question 6-1F

1 pt

Identify specimen 6F.

Question 6-3

1 pt

Which of the following specimens is often found as a secondary mineral?

A. 6AB. 6BC. 6CD. 6D

Question 6-4

1 pt

What is the silicate structure of Specimen 6A?

A. NesosilicateB. SorosilicateC. InosilicateD. Phyllosilicate

Question 6-5

1 pt

Specimen 6B has two planes of cleavage that have an angle of approximately…

A. 60 degreesB. 90 degreesC. 120 degreesD. 150 degrees

Question 6-6

1 pt

Which silicate structure has the highest resistance to weathering?

A. NesosilicateB. InosilicateC. CyclosilicateD. Tectosilicate

Question 6-7

1 pt

What is the white region with no minerals called?

Question 6-8

2 pts

According to the diagram, alkali feldspars contain a mix of what two metal cations?

Question 6-9

1 pt

Labradorite is a plagioclase feldspar mineral known for its iridescent effect, called labradorescence. What causes labradorescence?

A. Exsolution lamellaeB. Free-flowing sea of electronsC. Microbial stainingD. Anisotropic optical properties of microscopic grains

Question 6-10

3 pts

In albite, what percentage of cations are sodium, calcium, and potassium? We will accept answers within an acceptable range based on the diagram.

Station 7 - Biking

Question 7-1

1 pt

Which of the following is the BEST label for Arrow 1?

A. Heat and PressureB. Compaction and CementationC. MeltingD. Weathering

Question 7-2

1 pt

Which of the following is the BEST label for Arrow 8?

A. Heat and PressureB. Compaction and CementationC. MeltingD. Weathering

Question 7-3

1 pt

Suppose a new arrow, labeled 9, is drawn from sedimentary rock to magma. What would be the BEST label for this new arrow?

A. Heat and PressureB. Compaction and CementationC. MeltingD. Weathering

Question 7-4

2 pts · select all that apply

Select all of the following rock types that can be weathered to become sediment.

A. IgneousB. SedimentaryC. Metamorphic

Question 7-5

1 pt

Label 4

A. ZeoliteB. Prehnite-pumpellyiteC. BlueschistD. Eclogite

Question 7-6

1 pt

Label 7

A. HornfelsB. GreenschistC. AmphiboliteD. Granulite

Question 7-7

2 pts · select all that apply

Select the two facies that best exemplify contact metamorphism.

Question 7-8

1 pt

Does contact metamorphism typically produce foliation? Why or why not?

A. No - not enough heat for differential stressB. No - not enough pressure for differential stressC. Yes - heat creates differential stressD. Yes - pressure creates differential stress

Question 7-9

2 pts

Where does cataclastic metamorphism occur, and what is one rock that is formed at a zone of cataclastic metamorphism?

Question 7-10

2 pts

What feature is shown in the image above and what could have caused its appearance?

Station 8 - It's Special

Question 8-1

3 pts

Identify the following specimens: 8A: 8B: 8C:

Question 8-2

2 pts

Identify the following specimens: 8D: 8E: 8F:

Question 8-3

1 pt

What property is shown in Specimen 8A?

A. BirefringenceB. PiezoelectricityC. FluorescenceD. Diaphaneity

Question 8-4

1 pt

What property is shown in Specimen 8D?

A. BirefringenceB. PiezoelectricityC. FluorescenceD. Diaphaneity

Question 8-5

2 pts

Specimen 8C can show triboluminescence. Briefly explain what this means.

Question 8-6

1 pt

What gas is produced when Specimen 8F effervesces in powdered hydrochloric acid?

A. MethaneB. OxygenC. HydrogenD. Carbon dioxide

Question 8-7

2 pts

Specimens 8D and 8F both effervesce in HCl, but Specimen 8F effervesces more weakly. Why?

Question 8-8

2 pts

Specimen 8B is often naturally radioactive due to trace concentrations of what two heavy elements?

Question 8-9

1 pt

When three half-lives have passed, which of the following is the ratio between parent and daughter isotopes?

A. 3:1B. 1:1C. 1:3D. 1:7

Question 8-10

4 pts

Potassium-argon dating is used to determine the age of various igneous rocks. What type of radioactive decay occurs in Potassium-40 as it converts to Argon-40? Explain what happens in the nucleus of the atom and what particles (if any) are emitted.