Rock Cycle - Minerals (6A)
Post Lab 

  • Combining elements to form different minerals.
  • Exploring minerals made from silicon and oxygen.
  • element
  • mineral
  • worksheet
  • Googoplex

Students make a model of the silica tetrahedron.

Large crystal of quartz (about 1 meter)


Quartz is a silicate mineral. All silicate minerals share the same basic building block elements: silicon (Si) and oxygen (O) in the molecular configuration SiO4. This compound is called silica and referred to as a silica tetrahedron. as shown below. The large ball represents oxygen and the smaller ball represents the silicon. These oxygen atoms define a tetrahedral shape, with one oxygen atom at each points.

Silicate minerals occur in a great variety because, in addition to joining with other elements, silica tetrahedra can join with each other, creating rings, chains, double chains, sheets, framework, and other three dimensional silicate structures.

  1. Students can discover just how many tetrahedra combinations are possible. Each pyramid on the sheet represents a silica tetrahedron. Have them cut out the separate silicon tetrahedron.
  2. Make them arrange the pyramids into a pattern that can repeat itself. The different patterns would be equivalent to some type of silicate minerals.
  3. If you have Googolpex, have the students construct three-dimensional tetrahedron models. Have them point out where the oxygen and silicon atoms are located. With both the Googolplex and paper models the corners represent the oxygen atoms. The centrally located silicon atom is not present, but tell the students to assume it is inside the structure.
  4. Review the tetrahedra combinations made by the students. Explain that these represent just a small portion of the many silicate minerals that are present in the Earth’s crust. These make up the thousands of silicate minerals.

    "A" represents a sheet silicate; "B" represents a chain silicate; "C" represents a single or double: and "D" represents a ring silicate.

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