Crystals and Crystal Gardens You Can Grow 0531108899, 9780531108895

Citation preview

CRYSTALS

im

AND CRYSTAL GARDENS YOU CAN GROW BYJEANSTANGL

t

fe

1

BOSTON PUBLIC LIBRARY

J

)

>

X

X ^

/

CRYSTALS

AND CRYSTAL GARDENS

YOU CAN GROW

J

CRYSTALS AND

CRYSTAL GARDENS

YOU CAN GROW BY JEAN STANGL

Franklin Watts

New

York * London * Toronto * Sydney

A

First

Book * 1990

BRIGHTON

Library of Congress Cataloging-in-Publication Data

Stangl, Jean.

Crystals and crystal gardens you can grow/by Jean Stangl. p.

cm.— (A-First

book)

Includes bibliographical references.

Summary: Provides crystals, tips for

scientific

explanations for the formation of

growing them, and instructions

for

experiments.

ISBN 0-531-10889-9 l.

Crystals

— Juvenile

literature. I.

Title.

[1.

II.

literature.

Crystals

Title:

2.

Crystals

— Experiments.

— Growth — Juvenile 2.

Experiments.]

Crystal gardens you can grow.

QD921.S66 548'. 5 '078

— dc20

Copyright

©

III.

89-38999

CIP

AC

1990 by Jean Stangl © 1990 by Joe Le Monnier

Illustrations copyright

All rights reserved

Printed in the United States of America

5

4

Series.

1990

3

2

For Kenna,

who

likes to

grow

crystal gardens

Cover photograph courtesy of: American Museum of Natural History Photographs courtesy Photo Researchers: pp. 10 (Charles

of:

Falco), 14

(Nuridsany/

Perrennou), 15 (Pat Lynch), 16 (Chemical Design Ltd.), 20 (Gary Ladd), 25 (Mich Winter), 26 top (L. West), 31 (Dr. Jerry Burgess),

44 top (Jerry Schad), 44 bottom (Nuridsany/Perrennou); Taurus Photos: pp. 18 (Alfred Pasieka), 21 (Don/Pat Valenti), 22 top left

(Lenore Weber); Bruce Coleman: pp. 19 (E.R. Degginger), 22 left, 32 (both Jane Burton); American Museum of

bottom

Natural History: pp. 22 both right, 23

Illustrations

all,

24, 26

by Joe Le Monnier

bottom.

CONTENTS

Crystal Formations

11

Crystals You

Can Grow

30

Magic Crystal Gardens 46

How

Does Your Crystal Garden Grow?

58 For Further Reading 61

Index 62

CRYSTAL

FORMATIONS

Every day you see many different crystals. You probably even eat some! Did you eat any salt or sugar today? If so, then you ate some crystals, for both salt and sugar are crystals. ,

A

grain of salt

few grains of

salt

is

on

a tiny cubelike crystal. Place a a piece of black paper.

the salt grains with a magnifying glass.

Look

at

What do you

on the paper. Do they crystals? No, because the

see? Place a few grains of sugar

look the same as the

salt

sugar crystals have a different shape. Matter is everything that makes up the world, and all matter is made up of atoms, or arrangements of atoms called molecules. (An atom is the basic unit 11

of matter,

and molecules are similar or

different

atoms chemically bound together.) All matter comes solid, liquid, or gas. Water can in one of three forms take all three of these forms. It can be liquid, like the water you drink; gas, like steam vapor from boiling

—

water; or solid, as it

becomes

when it is placed in the freezer until

ice.

A crystal is a

form of a substance; in it, the atoms or molecules are arranged in an orderly pattern that is repeated over and over again throughout the whole crystal. The atoms are like tiny building blocks, and the crystal is made up of millions of atoms that fit together in their own special pattern to form that crystal. Salt crystals are shaped like cubes. In other crystals, the atoms or groups of atoms are arranged in different shapes.

solid

Most

scientists believe there are

seven types of crystals. Most nonliving substances are

made up

of crys-

diamonds, and snowflakes are all made up of crystals. However, early in history, scientists thought that only ice and the clear, colorless mineral called rock quartz were crystals. After much tals. Salt,

sugar, sand,

research and

many

experiments, they discovered

can be found in materials that are colored or colorless, hard or soft enough to be cut with a knife, and in some substances that can be melted, that crystals

*

12*

*

13*

Snowfiakes are the miniwonders of nature, with their complexity and beauty.

14*

When

heated to a certain point, gold becomes a liquid. But one thing all crystals have in common is that they have a definite shape. They also

such as gold.

have

flat

surfaces, called faces.

these faces meet,

you

Where two

or

will find angles (or

more

of

edges or

corners).

This false-color

photo of table salt

shows the

crystal's

many faces.

When you look at grains of salt with your magnisome may not appear to be perfect cubes. The reason for this is that some crystals do not form under ideal conditions, that is, undisturbed by other fying glass,

minerals that are starting to crystallize (become crys-

Some

might also appear chipped or nicked from rubbing against each tals).

of the crystals

15

to

be

other.

Crystallographers study of crystals. Here

is

many

different types

a computer graphic of a

molecule of a high-temperature superconductor,

showing

the material's crystal structure.

16*

Crystallography crystallographer

is

is

the study of crystals,

a scientist

who

and a

studies the ar-

rangement of the atoms that make up crystals. This book will help you begin to understand crystals and will tell you where you can find different types of crystals. Before you are through, you will also know how to make crystals and grow crystal " gardens. "

WHERE TO FIND CRYSTALS Most minerals and rocks

are

made up

of crystals.

Minerals are nonliving chemical substances that are found in nature. The minerals that make up rocks, sand, and gravel provide us with familiar examples of

The minerals sulfur, copper, and silver, and the graphite used in pencils, are sometimes found as

crystals.

naturally occurring crystals.

Rocks are usually made up of two or more kinds of minerals. Quartz, the common mineral found in

many Quartz

types of rocks, crystals

may be

is

often called rock crystal.

transparent or colored, but

they are always six-sided (as long as their growth

is

not interfered with by that of other crystals).

The sea is a giant storehouse of minerals. Driedup lakes and oceans have deposited layers and layers 17*

Quartz, or rock crystal, a

common It

mineral found in rock.

can be quite dazzling

the eye

is

and

is

to

always six-sided. 18*

of minerals.

mineral,

is

About one-third

of the world's salt, a

harvested from the ocean.

an example of a rock that is not made up of minerals. It is formed from plants that died many millions of years ago. Sugar is a crystal, but it is not a mineral. Sugar comes from plants, either sugarcane Coal

is

or sugar beets.

Look for rocks in your yard, the park, empty lots, or riverbeds. You can find white, black, and other colors of crystals in sand and gravel. The jagged edge of a freshly broken rock or a shiny rock soaked in

water will provide some interesting discoveries.

Sand

often con-

tains crystals of

many

different

colors, sizes,

and

shapes. This sand is

from a beach in

Saskatchewan.

* 19

Petrified

wood from

the Petrified Forest

National Park in Arizona

Shale, marble, slate, granite,

and

petrified

wood

contain crystals that can be found with your magnify-

you can't find any rocks with crystals, collections of rocks can be seen in museums, gem shows, county fairs, and hobby shops. A geode looks like an ugly brown rock. But when it is split open, you can see that its hollow center is surrounded by beautiful black, purple, and colorless ing glass.

If