Diamond and silicon form similar, covalently bonded, giant structures. For silicon, each atom is covalently bonded to four other atoms located at the corners of a tetrahedron. Silicon and diamond have similar properties except that silicon is a semi-conductor and conducts electricity. Silicon only conducts electricity when impure or heated. Silicon is used in integrated circuit technology, electrical components and digital electronics, as it is cheap and abundant. Heating coke and sand in electric furnace make silicon. It is a hard, green to bluish black, sharp crystal.

Manocrystalline silicon carbide is a semi-conductor material. A crystal of silicon carbide is harder than silicon, and the electron bond between the silicon and carbon atoms is extremely strong. Silicon carbide is a good conductor of heat and electricity. It is resistant to radiation and many chemicals. One application of silicon carbide is for compact power supply units with extremely low loss, which would also keep the power supply network free of electric smog (the unwanted interference frequencies resulting from the use of computers). Silicon carbide is also suited for space-saving control units for variable-speed drive which are generally mounted directly on the mortar.