Rocks and Rock Cycle

Earth processes form many different types of minerals and gems. One example is a mineral-like substance known as opal. Opal can be found in different areas across the Earth, such as Louisiana, Nevada, and Mexico. Australia is estimated to produce as much as 90 percent of the world's opal supply. Map 1 shows some of the major opal deposits in Australia. The process of mineral and gem formation, shown in Figure 1, can help explain how opal is distributed. When sandstone is weathered, it releases grains of sand. Water can then move the sand and other minerals into the cracks formed in other types of rock along the way. When the water evaporates, sand and other materials are left behind. This mixture of sand and other minerals hardens over time, eventually forming opal.

The locations of mineral and gem formation depend on different Earth processes. Some gems need heat, extreme pressure, or even a certain type of rock layer to form.

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Which location in the figure shows where opal is most likely to form?

​​

• Location 1

• Location 2

• Location 3

• Location 4

Tags

NGSS.MS-ESS2-2

NGSS.MS-ESS3-1

Earth processes form many different types of minerals and gems. One example is a mineral-like substance known as opal. Opal can be found in different areas across the Earth, such as Louisiana, Nevada, and Mexico. Australia is estimated to produce as much as 90 percent of the world's opal supply. Map 1 shows some of the major opal deposits in Australia. The process of mineral and gem formation, shown in Figure 1, can help explain how opal is distributed. When sandstone is weathered, it releases grains of sand. Water can then move the sand and other minerals into the cracks formed in other types of rock along the way. When the water evaporates, sand and other materials are left behind. This mixture of sand and other minerals hardens over time, eventually forming opal.

PART A: Based on the information in the stimulus and Map 1, which statements best explain why opal is found in places such as Australia? Select the two correct answers.​

• Australia has large amounts of sandstone and silica.

• Opal can only be formed where an ocean comes in contact with land.

• An inland sea once covered central to eastern Australia.

• Australia has a very hot, desertlike climate in most areas.

• Australia has very few active volcanoes across the continent.

Tags

NGSS.MS-ESS2-2

NGSS.MS-ESS3-1

Earth processes form many different types of minerals and gems. One example is a mineral-like substance known as opal. Opal can be found in different areas across the Earth, such as Louisiana, Nevada, and Mexico. Australia is estimated to produce as much as 90 percent of the world's opal supply. Map 1 shows some of the major opal deposits in Australia. The process of mineral and gem formation, shown in Figure 1, can help explain how opal is distributed. When sandstone is weathered, it releases grains of sand. Water can then move the sand and other minerals into the cracks formed in other types of rock along the way. When the water evaporates, sand and other materials are left behind. This mixture of sand and other minerals hardens over time, eventually forming opal.

Part B

Which statement best explains how the conditions identified in Part A affect the availability of opal?​

• Weathering processes no longer occur in Australia, so no new opal is formed.

• Gems do not need an exact combination of elements or minerals to form, so opal forms more easily.

• Opal formation occurs over large periods of time, so the number of opal deposits is limited.

• Volcanoes in Australia no longer provide high temperatures and pressures, so no new opal is formed.

Tags

NGSS.MS-ESS2-2

NGSS.MS-ESS3-1

Certain steps in the mineral extraction process can often have a lasting impact on Earth. Which one is a primary environmental impact in the opal extraction process.

• Risk of flooding in the area decreases.

• Local vegetation is damaged or removed.

• Concentration of minerals in the ground is small.

• Animals move to new locations in search of food sources.

Tags

NGSS.MS-ESS3-3

NGSS.MS-LS2-4

Certain steps in the mineral extraction process can often have a lasting impact on Earth. Which one is a secondary environmental impact in the opal extraction process.

• Risk of flooding in the area decreases.

• Local vegetation is damaged or removed.

• Concentration of minerals in the ground is small.

• Animals move to new locations in search of food sources.

Tags

NGSS.MS-ESS3-3

NGSS.MS-LS2-4

Which of these can transform metamorphic rock into igneous rock?

• heat and pressure

• melting and cooling

• pressure and melting

• deposition and cementation

Tags

NGSS.MS-PS1-4

What is number 1?

• heat pressure

• melting

• weathering

• cooling/crystallization

Tags

NGSS.MS-ESS2-1

What is number 2?

• heat pressure

• melting

• weathering

• cooling/crystallization

Tags

NGSS.MS-ESS2-1

What is number 3?

• heat pressure

• melting

• weathering

• cooling/crystallization

Tags

NGSS.MS-ESS2-1

What is number 4?

• heat pressure

• melting

• weathering

• cooling/crystallization

Tags

NGSS.MS-ESS2-1