WHAT IS COLOR?

"I feel foolish asking, but WHAT IS COLOR?"
"The color of a mineral is the color of a fresh, unweathered surface seen in white light."
"I take it that color is very useful in identifying minerals?!"
"Yes and no... There are some minerals for which the color is a constant. For example, malachite is always green! For those minerals, color is very helpful in identifying them!"
"Cool!"
"But for many other minerals, color is not a constant! For example, quartz comes in a whole bunch of colors! The different color varieties of quartz have their own names - purple amethyst, yellow citrine, rose quartz, smoky quartz, milky quartz, and so on! And then there's colorless quartz, called 'rock crystal'!"
"So why aren't they different minerals if they have different colors and different names?"
"They're all quartz because they have essentially the same chemical composition and the atoms are arranged in the same way! The different colors that the same mineral can have are due to very minute variations in composition or because they have tiny inclusions of different minerals in them that affect the color! In other words, the similarities are judged more important than the differences!"
"Do we need to know the different names for the different color varieties of the same mineral?"
"NO...For those starting to learn about minerals, the important thing is to know the main name of the mineral! We won't worry about the names of the varieties!"
"Whew! Thank goodness!"
"OK!! We take care of you, Lou!"


© 2010, David J. Leveson/Revised by G.Rocha and Michelle O'Dea