Page 21 - Curriculum Visions Dynamic Book

Because of its poor reactivity, it is used widely to make containers. Silicon carbide is an important abrasive. It is also an ingredient in steel.
Geology
Silicon is not found as a native element. It mostly forms an oxide that is the common mineral quartz. Forms of quartz include rock crystal, amethyst, agate, flint, jasper and opal. Other more complex minerals containing substantial amounts of silica include hornblende, feldspar and mica. Silicon makes up about 28% of the Earth’s crust, making it the second most common element in the crust after oxygen.
 Silicates, a combination of silicon and oxygen, form the most widely occuring minerals.This is a piece of agate.
Biology
Silica is used by some living things to make their skeletons. Birds eat sand because of their need for silicon.The presence of silicon dust can cause a lung inflammation called silicosis.
 Silicon is used in computer technology.
21
 Silicon ceramics are useful because they can sustain high temperatures for long periods without melting.This is a ceramic crucible used in chemistry laboratory demonstrations.