4 A crystal is a certain type of solid object It is a form of matter Scientists describe mat ter or everything that can be seen according to the way it is made All matter is made up of tiny parts called atoms and molecules If all those parts are arranged in a regular repeating pattern then the object is a crys tal The outsides of crystals have a regular pattern of flat surfaces that meet in sharp corners WHAT ARE CRYSTALS Different substances form different crystal shapes But all crystals of the same substance have the same shape
5 Most solid matter that is not alive is made up of crystals Common substances such as sugar and salt are made of crystals So are metals such as gold silver copper and iron Diamonds emeralds and other gems precious stones are also crystals Some objects are not made of crystals however Glass is one such example Its molecules are not arranged in any particular pattern Atoms are tiny particles that are the basic building blocks of all matter Atoms can be combined with other atoms to form molecules but they cannot be divided into smaller parts by ordinary means VOCABULARY Crystals include lovely precious stones also called gems such as diamonds and emeralds
