Silicon
A chemical element that has semiconducting properties. It is one of the most commonly used substances in modern computers and electronics. It is hard and brittle.
Please note that it is spelled siliCON, with no “E” at the end. It is NOT siliCONE which is a man-made, usually transparent, rubbery substance that is used for various things such as adhesives, sealants, cooking utensils, etc. These two words are often mixed up due to their similar spelling.