Chemical substance made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride) and refined sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical. Chemical substances exist as solids, liquids, gases, or plasma, and may change between these phases of matter with changes in temperature or pressure. Chemical substances may be combined or converted to others by means of chemical reactions. Forms of energy, such as light and heat, are not matter, and are thus not "substances" in this
Composition of matter may be produced by mechanical or chemical operations, and its result may be a compound substance resolvable into its constituent elements by mechanical processes, or a new substance which can be destroyed only by chemical analysis. A newly synthesized chemical compound or molecule may be patented as a composition of matter. Patents have been allowed on transitory products, such as short-lived chemical intermediates. In "Diamond v. Chakrabarty", the United States Supreme Court held that a genetically-altered living microorganism was patent-eligible subject matter. The "Chakrabarty" Court said that "we must determine whether respondent's micro-organism constitutes a 'manufacture' or 'composition of matter'