Rocks and Minerals Quiz

Grade 3 · Science · Quiz

Test your knowledge of rock types, minerals, and how rocks form.

Questions

Which rock type forms from layers of sand, mud, or shells pressed together?
1. Igneous
2. Metamorphic
3. Sedimentary
4. Volcanic
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Answer: Sedimentary
Sedimentary rocks form when sediment like sand, mud, and shells settles in layers and is slowly compressed into rock by the weight above it.
Granite is an example of an igneous rock.
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Answer: True
Granite is a coarse-grained igneous rock that forms when magma cools slowly deep underground, allowing large mineral crystals to grow.
Marble is a ___ rock that forms from limestone.
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Answer: metamorphic
Marble forms when limestone is put under extreme heat and pressure, recrystallizing the minerals inside. It's widely used for sculpture and building.
What is magma called once it reaches Earth's surface?
1. Granite
2. Lava
3. Sediment
4. Obsidian
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Answer: Lava
Magma is the term for melted rock underground. Once it erupts and reaches Earth's surface, it's called lava.
Metamorphic rocks form from cooled lava.
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Answer: False
Metamorphic rocks form when existing rocks are changed by heat and pressure inside Earth. Rocks that form from cooled lava are igneous rocks.
Which property would a geologist NOT use to identify a mineral?
1. Color
2. Hardness
3. Weight of the rock pile
4. Luster
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Answer: Weight of the rock pile
Geologists identify minerals by color, luster, hardness, streak, and cleavage. The weight of a whole pile of rocks doesn't help identify individual minerals.
A natural solid found in Earth with its own specific chemical makeup is called a ___.
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Answer: mineral
Minerals are natural inorganic solids with a definite chemical composition, like quartz (SiO2) or calcite (CaCO3). They are the building blocks of rocks.
Obsidian forms when lava cools very quickly.
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Answer: True
Obsidian is volcanic glass. When lava cools so fast there's no time for crystals to form, the result is smooth, glassy obsidian.
In the rock cycle, what can cause a rock to become metamorphic?
1. Wind and rain erosion
2. Heat and pressure underground
3. Freezing and thawing
4. Depositing in water
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Answer: Heat and pressure underground
When rocks are buried deep in Earth and exposed to high heat and pressure, their minerals recrystallize without melting, creating metamorphic rock.
The rock cycle happens over millions of years.
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Answer: True
The rock cycle is an incredibly slow process. Rock transformations typically take thousands to millions of years to complete.

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