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How to Identify Zircon Sand Grains

Sand is created by the erosion of igneous, metamorphic and sedimentary rocks. Small pieces are broken away by wind and water and transported long distances. By the time sand reaches its destination, emptied at the mouth of river or bay, sediments are small bits that may or may not be rounded and smooth, while other grains will remain angular and rough. The mineral composition of sand is directly related to the source rocks from which it derives, including zircon and other more abundant minerals such as quartz and feldspars.

Things You'll Need

6 sieve pans of varying Phi sizes (micrometer-sized screens)
Automated sieve shaker

Instructions

- 1
  
  Set of sieve pans -- smallest screen on bottom and largest on top
  
  Separate the sample of sand using Phi-scale sieve trays. The Phi scale is a logarithmic scale used to represent grain size and a U.S. Standard Sieve Mesh scale. Ideally, the 1/4 Phi scale works best using six or eight screens. Put the sample in the top pan and use an automated sieve shaker to separate the sand through the varying sizes of screens. It is also possible to shake the pans by hand for at least five minutes if an automated sieve shaker is unavailable.
- 2
  
  A 0.5 millimeter zircon crystal under an electron microscope.
  
  Use a mineral identification resource, available in libraries as well as online. The properties of minerals include their hardness or resistance to mechanical erosion. Because of this, separating the sand based on Phi size should also effectively separate them into mineral groups.
- 3
  
  A red cubic zirconia crystal.
  
  Determine the use for the zircon samples. Although most commonly known for its use as costume jewelry as cubic zirconia, zircon has many important scientific uses. Zircon has a high percentage of Uranium and Thorium content, both radioactive elements which cause internal damage to the mineral. As mentioned, zircon has a high specific gravity, but its density is decreased as it becomes damaged by the internal radiation. This can provide information on the dates of rock formations.

Rocks & Minerals