silicon-29

Silicon-29 is one of the three stable isotopes of silicon, making up 4.70 percent of naturally occurring silicon. The most abundant isotope is silicon-28 (92.21 percent), followed by silicon-30 (3.09 percent). Silicon itself is a nonmetallic chemical element, second only to oxygen in abundance in Earth's crust. It is found in rocks, sand, and clays, primarily as silicon dioxide or silicates. Silicon's properties are similar to carbon, and it is a crucial semiconductor in electronics. While elemental silicon is generally non-toxic, inhaling dust containing silicon dioxide can cause silicosis.1