E-waste contains different types of valuable materials. Most of the valuable substances are found in printed circuit boards (PCB) , which occur in relevant quantities mainly in the IT and Communication Equipment as well as Entertainment and Consumer Electronics. Besides well known precious metals such as gold, silver, platinum, and palladium also scarce materials like indium and gallium are also present.
Precious and scarce materials account for only a small percentage of the total weight. Nevertheless, the concentration of such metals, e.g. gold, is higher in a desktop computer than found in naturally occurring mineral ore.