PROBLEM: Why is quartz found in many different colors?

PREDICTION:

PROCEDURE:

Exercise I. The bottle of food coloring that you have represents a "pure" form of one element. The following volumes of food coloring represent a "trace" amount. The water represents quartz and the food coloring represents another element.

1. What happens when you put 1 drop of food coloring into 200 ml of water?

2. What happens when you put 4 drops of food coloring in the same 200 ml of water?

Exercise II. The samples that you have are composed mainly of silicon dioxide. Can you figure out what is in the various samples? Use the hints below to help.

rose color = titanium; purple or violet = iron; colorless = pure silicon dioxide; milky = fluid (not cause by an element); green = caused by small flakes of mica and hematite

CONCLUSION: What is similar about the different forms of quartz you examined? What is different?