Which of the following is not an example of pure gold restorative material?​

Direct gold restorations are the only type of restorations that use pure metal, namely gold, with the exception of one type of direct gold, i.e., electralloy. Direct gold materials can be classified into two main categories: precipitated gold and gold foil. Electralloy is an actual alloy of gold and calcium, with the calcium content in the range of 1%. Alloying induces some improvements in the mechanical properties of the pure gold through slip interference. The alloying process is done before atomization, and the particles are shaped exactly like mat gold. They, too, are subjected to sintering in order to make the specific “cake” or “strip” shapes. Ref: Marzouk .page 393