Mineral of the Month – The element, Silicon January 2022

In chemistry, an element is a pure substance consisting only of atoms that all have the same numbers of protons in their nuclei. Unlike chemical compounds, chemical elements cannot be broken down into simpler substances by any chemical reaction. In school we learned about elements via the Periodic Table of Elements.

There are 118 elements that have been identified and listed in the Periodic Table, 94 that occur naturally on Earth (depending on how you count them). The lightest elements are hydrogen and helium (atomic numbers 1 and 2); the heaviest is uranium (atomic number 92). The remaining 24 heavier elements, not found today on Earth, have been produced artificially. Only around 32 elements, such as silver and gold, can be found in an uncombined, relatively pure form. Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. For example, air is primarily a mixture of the elements nitrogen, oxygen, and argon, but also can contain compounds including carbon dioxide and water. 

Silicon (atomic number 14) makes up 27.7% of the Earth’s crust by mass and is the second most abundant element (oxygen is the first). It does not occur uncombined in nature, but usually mixes with oxygen to form silica minerals such as quartz, amethyst, agate, flint, and opal. Pure silicon has the same crystal structure as diamond, which is made of carbon – the element that sits above silicon in the periodic table.

It is important to point out that silicon and silicone are quite different. Silicon is a naturally occurring element, number 14 on the periodic table. Silicone is a synthetic material made of silicon–oxygen polymers used for a variety of applications.

When ultrapure, silicon is a gray solid with a glossy sheen. Although it looks like a metal, silicon is classified as a metalloid – it conducts electricity only under certain conditions – making it well-suited for the electronics industry (e.g., computer chips).

The silicon images shown above and in the photos below have been purified from silicon dioxide quartz (silica). The manufacture of this silicon (which is 98% pure) occurs in two stages. The oxygen is removed to produce metallurgical grade silicon, such as the specimens shown here. It is then further refined to produce semiconductor grade silicon.

If it were not for the element silicon, there would be no agates on Earth. Thank you silicon!


Periodic Table image: https://commons.wikimedia.org/wiki/File:Periodic_table_large.png

Silicon element: https://commons.wikimedia.org/wiki/File:Electron_shell_014_Silicon.svg

Silicon info: https://commons.wikimedia.org/wiki/File:Silicon.svg

Silicone: https://commons.wikimedia.org/wiki/File:Maryse_cuisine.JPG

Silicon computer chip: https://commons.wikimedia.org/wiki/File:VIA_Nano_E-Series_Chip_Image_-_45_Degree_(4542811524).jpg

The remaining photos on this page were taken by Karen Brzys.

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