The same word was also used for the substance amber, likely because of the pale yellow colour of certain varieties, and it is from amber's electrostatic properties that the modern English words "electron" and "electricity" are derived. Electrum was often referred to as white gold in ancient times, but could be more accurately described as "pale gold". The modern use of the term white gold usually concerns gold alloyed with any one or a combination of nickel, silver, platinum and palladium to produce a silver-coloured gold.