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Inside a Geode: Crystals Hidden in Stone

5th grade nonfiction passage about how geodes form: 200 words, six questions, an answer key and vocabulary.

5th grade nonfiction how geodes form 200 words

Inside a Geode: Crystals Hidden in Stone

A geode looks like a plain, bumpy rock. It is gray or brown, about the size of a grapefruit, and you might walk right past it. But when someone cracks it open, the inside can sparkle with crystals. How did a hollow space filled with glittering points end up inside solid stone?

The story begins with an empty pocket. Sometimes a gas bubble gets trapped in cooling lava. In other cases, a hollow is left where an animal burrow or a bit of wood once sat in soft rock. Over a very long time, the pocket stays buried.

Rain soaks into the ground and picks up tiny amounts of minerals as it moves through the soil and rock. This mineral water seeps into the empty pocket. Drop by drop, some of the water dries up or cools, and the minerals it carried are left behind on the walls. They build up, layer after layer, and form crystals. A common mineral in geodes is quartz.

The outer shell is usually harder than the rock around it. That is why, when the rest of the hillside wears away, the round geode may be left lying on the ground, waiting to be found.

Questions

  1. What does the outside of a geode look like? in the text

  2. How can an empty pocket form inside a rock? in the text

  3. How do minerals get into the pocket? in the text

  4. What forms on the walls as the water dries up or cools? in the text

  5. Why might a geode be found lying on the ground? think about it

  6. Why do crystals in a geode take a very long time to grow? think about it

Words to know

geode
a rock with a hollow space lined with crystals
hollow
empty on the inside
minerals
natural solid materials found in rock and earth
seeps
flows slowly through tiny openings
quartz
a hard, common mineral that can form clear crystals
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One passage, three levels

The same topic and facts written three ways, so a mixed class can read and talk about one text. Each group’s sheet shows only a shape; the key says which is which.

● Easier · 167 words · Flesch-Kincaid grade 3.5

A geode looks like a plain, bumpy rock. It is gray or brown and about the size of a grapefruit. But when you crack it open, the inside can sparkle with crystals. How can a rock hide such a thing?

It starts with an empty pocket. A gas bubble can get stuck in cooling lava. Or an animal burrow or a bit of wood can leave a hollow in soft rock. The pocket stays buried for a very long time.

Rain soaks into the ground. It picks up tiny bits of minerals from the soil and rock. This mineral water seeps into the empty pocket. Drop by drop, the water dries up or cools. The minerals stay behind on the walls. They build up layer after layer and make crystals. Quartz is a common mineral in geodes.

The outer shell is harder than the rock around it. So when the hillside wears away, the round geode may be left lying on the ground, waiting to be found.

▲ This passage · 200 words · Flesch-Kincaid grade 5.4

A geode looks like a plain, bumpy rock. It is gray or brown, about the size of a grapefruit, and you might walk right past it. But when someone cracks it open, the inside can sparkle with crystals. How did a hollow space filled with glittering points end up inside solid stone?

The story begins with an empty pocket. Sometimes a gas bubble gets trapped in cooling lava. In other cases, a hollow is left where an animal burrow or a bit of wood once sat in soft rock. Over a very long time, the pocket stays buried.

Rain soaks into the ground and picks up tiny amounts of minerals as it moves through the soil and rock. This mineral water seeps into the empty pocket. Drop by drop, some of the water dries up or cools, and the minerals it carried are left behind on the walls. They build up, layer after layer, and form crystals. A common mineral in geodes is quartz.

The outer shell is usually harder than the rock around it. That is why, when the rest of the hillside wears away, the round geode may be left lying on the ground, waiting to be found.

■ Harder · 219 words · Flesch-Kincaid grade 7.6

A geode appears to be nothing more than a plain, lumpy stone. Gray or brown and roughly the size of a grapefruit, it is the kind of rock that most people would walk past without a second glance. Yet when someone cracks it open, the interior may glitter with crystals. How could a hollow space lined with sparkling points end up concealed inside solid stone?

The story begins with an empty pocket. Occasionally, a gas bubble becomes trapped in cooling lava. In other cases, a cavity is left behind where an animal burrow or a fragment of wood once rested in soft rock. For an enormous span of time, the pocket remains buried underground.

Meanwhile, rain soaks into the soil and collects tiny amounts of minerals as it percolates through the earth and rock. This mineral-rich water seeps into the empty pocket. Drop by drop, some of the water evaporates or cools, and the minerals it carried are deposited on the walls. They accumulate, layer upon layer, and form crystals. Quartz is one of the most common minerals found in geodes.

The outer shell is generally tougher than the rock surrounding it. That is why, when the rest of the hillside erodes, the rounded geode may be left sitting on the ground, waiting for someone to discover it.

Download as one PDF

How to use it

  1. Press Read it big (or B) to put the text on the projector, or Full screen (F) to fill the whole screen.
  2. Ask the questions one at a time and use Show answer when the class has decided. A shows or hides every answer.
  3. Print student copy for the class, or Print with answers for yourself.

Ideas for class

  • Before reading, put geode, hollow, minerals, seeps and quartz on the board with their meanings from the Words to know section and have students predict what the text will be about.
  • Read it aloud once while students follow along, then have them reread it alone or with a partner. At a calm 100 words a minute it takes about 2 minutes to read aloud.
  • Use the Read it big button (or B) to put the text on the projector, and Show answer on one question at a time so the class commits to an answer first.
  • Question 5 asks the reader to infer. Ask students to point to the words in the passage that led them to their answer.
  • Ask students to write one question the passage did not answer, then look for the answer in a book or on a classroom screen.
  • Print the student copy for independent work and keep the answer-key copy for yourself.

Related

Questions

What reading level is "Inside a Geode: Crystals Hidden in Stone"?

It was written for 5th grade. It has 200 words and works out to a Flesch-Kincaid grade level of about 5.4. That is a formula's estimate from sentence length and syllables, and it is not a Lexile or a guided reading level, so check it against your students.

What do the questions ask?

There are six. 4 ask for something the text says directly and 2 ask the reader to work something out from clues. Each has an answer in the key, and the answers are written as a teacher would accept them, not as the only possible wording.

How long does it take to read?

About 2 minutes read aloud at 100 words a minute. For a one-minute fluency check, paste it into the fluency timer and use the word count.

Can I print it?

Yes. Print student copy gives the passage, the questions with lines to write on, and the word meanings. Print with answers gives the same page with the answers filled in. Both are made in your browser.

Is this passage from a published book?

No. It was written for Peabody Teach, so there is no book to buy and no login to read it.

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