Silicon nitride is a chemical compound of the elements silicon and nitrogen. Silicon is capable of directing the fragmentation through the beta-silicon effect. Polysilicon is distinct from monocrystalline silicon and amorphous silicon. Pure germanium is a semiconductor with an appearance similar to elemental silicon. Boron is a useful dopant for such semiconductors as silicon, germanium, and silicon carbide. Yttria is used as a sintering additive in the production of porous silicon nitride. Such elements include germanium, zinc, platinum, silicon, and boron. Fuels include aluminium, magnesium, titanium, zinc, silicon, and boron. Quartz is a hard, crystalline mineral composed of silicon and oxygen atoms. Indirect bandgap materials include crystalline silicon and Ge. The HIC detected heavy ions using stacks of single crystal silicon wafers. Phyllosilicate clays consist of layered sheets of aluminium and silicon oxides. The common oxide of silicon (SiO) is weakly acidic. The process begins with the production of monocrystalline silicon ingots.