- Abundant element - Chemical element - Element Si - A nonmetalic element analogous to carbon. It always occurs
combined in nature, and is artificially obtained in the free state,
usually as a dark brown amorphous powder, or as a dark crystalline
substance with a meetallic luster. Its oxide is silica, or common
quartz, and in this form, or as silicates, it is, next to oxygen, the
most abundant element of the earth's crust. Silicon is
characteristically the element of the mineral kingdom, as carbon is of
the organic world. Symbol Si. Atomic weight 28. Called also silicium.