Rock Cycle - Minerals (K)
Post Lab 

  • Exploring the various colors of quartz.
  • Learning that the same mineral may have more than one color.
  • mineral
  • quartz

Students color a drawing of a quartz crystal.

quartz crystal


Quartz is a very common gemstone. People think it is pretty enough to wear. Quartz is the most abundant mineral found on the Earth's crust. However, most quartz is not found in its six-sided crystal form shown in the picture above.

Some areas are known for their beautiful quartz crystals. The state of Arkansas produces some of the most beautiful clear crystals in the world. Brazil and India are also known for their quartz crystals.

Quartz is very hard, which makes it ideal for gems. Pure quartz is white or colorless, but is commonly found in almost any color imaginable. Since quartz is naturally clear, any chemical impurities will allow the color to "shine" through. Amethyst, tiger eye, adventurine, and agates are all varieties of quartz with impurities in them to cause their distinctive color.

  1. Discuss that quartz is a mineral. Explain that many minerals have pretty crystal shapes. Quartz forms hexagonal (six sided) prisms.
  2. Inform the students that quartz can be found in many different colors. If you have any jewelry like amethyst (purple), citrine (yellow-brown), agate (multicolored), adventurine (green), tiger's eye, or other stones of quartz, wear them to school and show the jewelry to the students. All these different types of jewelry are different forms of quartz.

    Amethyst is the purple variety of quartz and is a popular gemstone. If it were not for its widespread availability, amethyst would be very expensive. The name "amethyst" comes from the Greek and means "not drunken." This was maybe due to a belief that amethyst would ward off the effects of alcohol, but most likely the Greeks were referring to the almost wine_like color of amethyst.

    Citrine is any quartz crystal or cluster that is yellow or orange in color. Although, often cut as a gemstone, citrine is actually somewhat rare in nature. Most citrine on the market have been heat treated. Unfortunately citrine it is often confused with the more expensive orange_yellow topaz and is at times sold as topaz by unscrupulous dealers.

    Other forms of quartz include:

    Milky Quartz is the cloudy white variety.
    Rock crystal is the clear variety that is also used as a gemstone.
    Rose quartz is a pink to reddish pink variety.
    Smoky quartz is the brown to gray variety.

  3. Have the students color the worksheet. They can use just about any color!

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