OBJECTIVES:

• Learning that some minerals are gemstones.
• Discovering different birth stones.

VOCABULARY:

• gem
• mineral

MATERIALS:

• Gemstone worksheet
• Gem Display Kit
• Gems by Blueford and Doherty

Students observe and learn about birth stones.

BACKGROUND:

Are all gems minerals? A mineral is an inorganic, naturally occurring substance with distinct chemistry and crystalline structure. Gemstones are materials that have an economic or aesthetic value. Therefore, not all gemstones are minerals. For example, amber is solidified tree resin, so it is not a mineral.

Gemstones can be classified as either amorphous or crystalline. Amorphous gemstones have no orderly internal atomic structure and no naturally occurring shape. Glass, amber, and opal are examples. Crystalline gemstones are minerals; they have a definite and regular internal atomic structure. Examples include garnet, emerald, and ruby.

PROCEDURE:

1. Most students are familiar with their birth month's gemstone. Poll your students and see if you can list the months and the gems just from their answers.
    

2. Using the table below, review birth stones with your students. In some cases, a month may have more than one gemstone listed. Also, when a mineral is very common is acquires a common name used by most people. Remember that the proper scientific name and the common name refer to the same substance with the same chemical composition.
    

3. The Gemstone Worksheet  and the Gem Display Kit can help students visualize these substances. Many of the gems in the Gem Display are real, but have flawed structures, so they are not particularly valuable.

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