ROCK CYCLE UNIT REVIEWBy Mrs. Susan Dennison

2012-13

What are minerals?A mineral is a solid material, formed in nature, with particles arranged in a repeating pattern (crystals).

How do minerals form?Minerals form in many ways: in the mantle, at or near the surface, and from mineral-rich water.

Calcite is a mineral found in chalk. It can form near the Earth’s surface or in the ocean, when calcium, oxygen, and carbon combine in sea water. Some sea animals form calcite shells. Calcite also forms as water evaporates in limestone caves.

What are the properties of minerals?Mineral properties include: streak, luster, and hardness. Minerals can be tested for these.

Why are diamonds so hard?Diamonds are hard because the particles they are made of are bound together so tightly. They are formed in the lower crust/upper mantle where pressures and temperatures are extremely high. They will scratch all other minerals and can cut glass!

Diamond mine in Siberia Polished, cut diamondsRough diamond

How do we use minerals?We eat and drink minerals, wear them as jewelry and makeup, build things with them, clean with them, and more!

What are gemstones?

Of the more than 3,000 minerals, about 100 are considered so beautiful and rare that they are called gemstones.

What are rocks?Rocks are materials made from one or more minerals. Earth is made of mostly rocks.

What are the 3 types of rocks? All rocks can be classified into three groups

based on how they were formed.

1. IGNEOUS2. SEDIMENTARY3. METAMORPHIC

No, NOT this type of rock!

How are igneous rocks formed?Igneous rocks form when melted rock hardens. Rocks formed from lava are fine-grained and rocks formed from magma are course-grained. Basalt is the most common igneous rock formed at Earth’s surface.

What is a common igneous rock used in construction?

Granite is a strong igneous rock often used for building. It is made from large grains of quartz, feldspar, and mica minerals joined together tightly.

What does “igneous” mean?

The word igneous comes from the Latin word ignis, which means “fire.” Think about why.

How are sedimentary rocks formed?

Sedimentary rocks are formed when, over a long time, layers of sediment weathered away and deposited are squeezed (compressed) and stuck together (hardened) in layers.

What are some types of sedimentary rocks we commonly see?

Conglomerate, sandstone, shale, and limestone are commonly seen sedimentary rocks.

How are metamorphic rocks formed?Metamorphic rocks are made of igneous and sedimentary rocks that have been changed by high heat and pressure. Even the minerals that make up the rocks are changed!

It's not hard to see that this metamorphic rock, called gneiss, has been intensely folded! This rock had to have been under very high pressure and temperature to allow it to fold like this without breaking.

Photo by Edward P. Klimasauskas

What does metamorphic mean?

The word metamorphic is made of two word parts, meta means “change,” and morphic means “form.” Think about why.

What is the rock cycle?The rock cycle is a description of the processes that change the solid Earth.

What are the processes involved in the rock cycle?

We have studied many of these in our previous geology unit!

1. Weathering2. Erosion3. Heat4. Pressure5. Melting6. Compaction7. Cementation

What is a good model to describe Earth’s rock cycle processes?

Bread can be used to model the rock cycle!

A loaf of bread is new, solidmaterial formed after heatingand cooling. It is like igneousrock.

Bread crumbs are “eroded” Pieces, or sediments. They can be layered in a pan, and squeezed together, like sedimentary rock.

A piece of toast has been changed by heat. It is like metamorphicrock!